Commit Graph

7417 Commits

Author SHA1 Message Date
Hui Su
649bc7df3e tracing: Fix crash passing ERR_PTR to kthread_stop()
event_test_stuff() calls kthread_run() and unconditionally passes the
returned task_struct pointer to kthread_stop(). kthread_run() returns an
error pointer such as ERR_PTR(-ENOMEM) when kthread creation fails, for
example under memory pressure during the boot-time event self-test.
kthread_stop() then dereferences the invalid pointer, crashing the kernel.

Check the result of kthread_run() before passing it to kthread_stop(). Use
WARN_ON() so that a failure to create the self-test thread does not go
unnoticed, matching the ring-buffer self-test fix in commit
91542863ab ("ring-buffer: Fix crash passing ERR_PTR to kthread_stop()").

Cc: stable@vger.kernel.org
Fixes: e6187007d6 ("tracing/events: add startup tests for events")
Link: https://patch.msgid.link/20260817120642.668375-3-sh_def@163.com
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-22 17:35:50 -04:00
Hui Su
a7318172aa tracing: Fix use-after-free with same-name named triggers
When two hist triggers on different events are registered with the same
name=, the second one reuses the first as named_data.  Both are added to
tr->hist_vars by save_hist_vars() during event_hist_trigger_parse(),
because save_hist_vars() is called before event_trigger_register() while
the named reuse is only detected later, in hist_register_trigger().

In the named-data branch hist_register_trigger() then frees the second
histogram's hist_data via destroy_hist_data(), but never removes its
tr->hist_vars list entry, leaving a dangling pointer and leaking the
trace_array reference it holds.

A later hist trigger that references a variable makes find_var_file()
walk tr->hist_vars and dereference the freed hist_data.  The bug is
reproducible from userspace by writing three hist triggers to tracefs:

  cd /sys/kernel/tracing
  echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_switch/trigger
  echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_process_fork/trigger
  echo 'hist:keys=common_pid:vals=$x' > events/sched/sched_process_exit/trigger

The third write panics the kernel:

  BUG: KASAN: slab-use-after-free in find_var_file.part.0+0x272/0x290
  Read of size 8 at addr ffff888001f8a0e0 by task sh/1
  CPU: 1 UID: 0 PID: 1 Comm: sh Tainted: G      D          N
  Call Trace:
    find_var_file.part.0
    find_event_var
    parse_atom
    parse_expr
    __create_val_field
    event_hist_trigger_parse
    trigger_process_regex
    event_trigger_write
    vfs_write
    ksys_write
    do_syscall_64
    entry_SYSCALL_64_after_hwframe
  Allocated by task 1:
    event_hist_trigger_parse
  Freed by task 1:
    hist_register_trigger+0x618/0xa30
    event_hist_trigger_parse
  The buggy address belongs to freed 2048-byte region
  Oops: general protection fault ... RIP: find_var_file.part.0
  Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Fix by removing the hist_data from tr->hist_vars and releasing the
trace_array reference in the named-data branch of hist_register_trigger()
before freeing the hist_data.

Cc: stable@vger.kernel.org
Fixes: 6f86bdeab6 ("tracing: Fix bad hist from corrupting named_triggers list")
Link: https://patch.msgid.link/20260816100427.33642-3-sh_def@163.com
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-22 17:33:57 -04:00
Vincent Donnefort
a9a01be283 tracing: Fix logged instance name on creation failure
When boot instance creation fails, the kernel incorrectly logs "(null)"
as the instance name because strsep() consumes curr_str entirely during
parsing.

Print the properly parsed name variable instead. And while at it log
the error code.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260807085423.4175161-1-vdonnefort@google.com
Fixes: cb1f98c5e5 ("tracing: Add creation of instances at boot command line")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-22 10:41:58 -04:00
Linus Torvalds
ed3b875bea mm.git review status for mm-hotfixes-stable..mm-stable
Everything:
 
 Total patches:       501
 Reviews/patch:       1.66
 Reviewed rate:       70%
 
 Excluding DAMON:
 
 Total patches:       356
 Reviews/patch:       2.26
 Reviewed rate:       90%
 
 Excluding DAMON and selftests:
 
 Total patches:       329
 Reviews/patch:       2.31
 Reviewed rate:       92%
 
 Excluding DAMON, selftests and maple_tree:
 
 Total patches:       328
 Reviews/patch:       2.31
 Reviewed rate:       92%
 
 Summary of patch series in this merge:
 
 - The 2 patch series "mm: drop "sub" prefix from various places" from
   Dev Jain implements some page->folio conversion and a naming cleanup.
 
 - The 2 patch series "mm/kasan: remove redundant initialization for
   kasan_flag_write_only" from Igor Putko provides some KASAN cleanup work.
 
 - The 2 patch series "mm/filemap: reduce unnecessary xarray lookups"
   from Chi Zhiling provides a small speedup in the pagecaache read code.
 
 - The 4 patch series "mm/percpu: Fix possible NOFS/NOIO reclaim
   recursion" from Kaitao Cheng improves a few things in the vmalloc code -
   mainly the avoidance of GFP_KERNEL allocations when the caller asked for
   GFP_NOFS or GFP_NOIO.
 
 - The 3 patch series "mm/kmemleak: avoid soft lockup when scanning task
   stacks" from Breno Leitao avoids a soft lockup watchdog trigger from the
   kmemleak scanning code in extreme situations.
 
 - The 6 patch series "mm/page_owner: misc cleanups" from Ye Liu is a
   collection of unrelated cleanups to the page_owner code.  For some
   reason lots of people have been working on the page_owner code this
   cycle.
 
 - The 4 patch series "mm: convert to walk_page_range_vma() to eliminate
   find_vma()" from Kefeng Wang simplifies and accelerates the page walking
   library function.
 
 - The 3 patch series "mm/migrate: preparatory cleanups for batch copy
   and offload" from Shivank Garg implements cleanups in the migration
   code.
 
 - The 4 patch series "mm/page_owner: add per-fd filter infrastructure
   for print_mode and NUMA filtering" from Zhen Ni provides per-fd
   filtering to page_owner in order to reduce the sometimes vast amount of
   output it can produce.
 
 - The 19 patch series "mm: Refactor bootmem gigantic hugepage
   allocation" from Muchun Song is a "set of fixes and preparatory cleanups
   around bootmem HugeTLB handling, sparse initialization ordering, and
   related vmemmap setup".
 
 - The 4 patch series "mm/zsmalloc: reduce lock contention in zs_free()"
   from Wenchao Hao reduces lock contention in zs_free(), which dominates
   the unmap path under memory pressure on Android (LMK kills) and on x86
   servers running zswap-heavy workloads.  Up to 1.83x improvement in
   microbenchmarking.
 
 - The 2 patch series "move alloc_tag.c file under mm/" from Suren
   Baghdasaryan does that.
 
 - The 6 patch series "samples/damon: handle damon_{start,stop}()
   failures" from SJ Park fixes improper handling of damon_start(),
   damon_stop(), and damon_call() failures across DAMON sample modules to
   prevent potential memory leaks, operation disruptions and use-after-free
   bugs.
 
 - The 11 patch series "mm/damon/sysfs: kobject_del() directories that
   users can create/remove" from SJ Park resolves an issue where delayed
   sysfs directory removal under CONFIG_DEBUG_KOBJECT_RELEASE causes
   creation failures due to duplicate directory names by adding missing
   kobject_del() calls before creating new directories.
 
 - The 3 patch series "mm: cleanup clear_not_present_full_ptes()" from
   David Hildenbrand cleans up the core pte handling code.
 
 - The 3 patch series "selftests/damon: misc fixes for test bugs" from
   Kunwu Chan fixes several bugs in the DAMON selftests.
 
 - The 2 patch series "selftests/damon: fix memcg_path staging handling"
   from Cheng Nie fixes a bug in _damon_sysfs.py for damos_filter
   memcg_path setup, and adds a test case for it in sysfs.py.
 
 - The 2 patch series "selftests/damon: test kdamond refresh_ms" from
   Ruslan Valiyev introduces selftest coverage for DAMON's refresh_ms sysfs
   feature by updating the test control module and verifying that scheme
   stats update automatically without manual intervention.
 
 - The 5 patch series "mm/damon: five misc fixups" from Akinobu Mita
   contains miscellaneous DAMON fixups.
 
 - The 2 patch series "mm/damon/core: detect internal variation above
   max_nr_regions/2" from Jiayuan Chen fixes DAMON's region splitting
   behavior when region counts exceed half the maximum budget by
   dynamically scaling down the split fraction as the limit approaches,
   preventing large regions from staying un-split, and adds corresponding
   KUnit test coverage.
 
 - The 6 patch series "mm: preparatory patches for PMD level swap
   entries" from Usama Arif refactors and cleans up PMD softleaf helpers,
   call sites, and architecture flags to lay the groundwork for a follow-up
   series that introduces PMD page table swap entries.
 
 - The 11 patch series "mm/damon: update, optimize, and clean up doc,
   tests, and code" from SJ Park updates DAMON design and ABI
   documentation, expands unit and selftest coverage, optimizes
   damon_commit_target_regions(), and cleans up recently added sysfs
   interface code for better readability.
 
 - The 2 patch series "mm/vmpressure: reduce CPU, memory and code
   overhead on cgroup v2" from Usama Arif optimizes vmpressure() by
   skipping unnecessary work on cgroup v2 for userspace event notifications
   and refactors v1-only eventfd handling into mm/memcontrol-v1.c to reduce
   memory overhead and code complexity.
 
 - The 10 patch series "selftests/mm: refactor pkey helpers and fix mmap
   error handling" from Hongfu Li refactors pkeys shared tracing and
   assertion helpers into a common file, unifies protection key selftests
   to use consistent diagnostic logging and assertions, and enforces
   standardized MAP_FAILED return checks for mmap() calls across the tests.
 
 - The 18 patch series "mm/damon: optimize out nr_accesses_bp" from SJ
   Park replaces the error-prone, continuously updated nr_accesses_bp field
   in damon_region with an on-demand moving sum function
   (damon_nr_accesses_mvsum()), reducing structure memory overhead and
   avoiding state corruption bugs.
 
 - The 6 patch series "Open HugeTLB allocation routine for more generic
   use" from Ackerley Tng decouples HugeTLB folio allocation from VMA
   dependencies by introducing hugetlb_alloc_folio(), enabling subsystems
   like guest_memfd to allocate HugeTLB folios without standard VMA
   reservations or pseudo-VMAs.
 
 - The 3 patch series "mm/damon: provide pseudo moving sum probe_hits"
   from SJ Park integrates DAMON's probe_hits attribute counter into the
   pseudo moving sum infrastructure, enabling real-time, online monitoring
   without waiting for full aggregation intervals.
 
 - The 18 patch series "mm: Some cleanups for page allocator APIs" from
   Brendan Jackman simplifies and refactors the page allocator entry points
   and flags by unifying allocation paths, adding internal alloc_flags
   arguments, and eliminating redundant __ prefixed alloc_pages variants.
 
 - The 5 patch series "Fix incorrect access of hugetlb pte entries" from
   Dev Jain enforces the consistent use of huge_ptep_get() instead of
   ptep_get() for HugeTLB entries and fixes an unaligned address issue in
   arm64's huge_ptep_get() implementation.
 
 - The 8 patch series "mm/damon: validate all parameters in the core"
   from SJ Park consolidates parameter validation into the DAMON core
   specifically within damon_start() and damon_commit_ctx() to centralize
   error checking, eliminate caller-side redundant checks and to improve
   maintenance efficiency.
 
 - The 3 patch series "tools/mm/page_owner_sort: fix filtering and
   cleanup issues" from Yichong Chen renames is_need() to filter_record()
   for clearer return semantics, fixes per-record allocation memory leaks
   and bounds output copies in search_pattern() to address an existing
   buffer issue.
 
 - The 4 patch series "memcg: bail out reclaim when memcg is dying" from
   Jiayuan Chen mitigates a system-wide stall which occurs when a cgroup is
   removed while one of its memory control files is doing synchronous
   reclaim.
 
 - The 5 patch series "mm/memory-failure: add panic option for
   unrecoverable pages" from Breno Leitao introduces an opt-in
   vm.panic_on_unrecoverable_memory_failure sysctl that immediately panics
   the kernel on unrecoverable memory errors in kernel-owned pages to
   preserve error context and prevent delayed, silent data corruption.
 
 - The 11 patch series "mm/damon: refactor damon_{start,stop,commit}()
   for simple error handling" from SJ Park refactors the DAMON core API
   functions to guarantee that all contexts are fully stopped when
   damon_start(), damon_stop(), or damon_commit() fail, eliminating the
   need for complex and error-prone caller-side cleanup code.
 
 - The 5 patch series "Keep tail page private zero at free and folio
   split" from Zi Yan adds checks to ensure tail_page->private is zero when
   freeing compound or high-order pages and when promoting tail pages
   during large folio splits.  By validating these fields at free and split
   time, it allows the removal of redundant private field clearing inside
   prep_compound_tail().
 
 - The 4 patch series "mm: drop redundant lru_add_drain in anon folio
   reuse paths" from Barry Song eliminates redundant lru_add_drain() calls
   in wp_can_reuse_anon_folio() and do_swap_page() to reduce LRU lock
   contention and system overhead.
 
   By validating folio refcounts against the LRU cache before draining
   and removing unnecessary drains in the swap path, it achieves up to a
   30.5% reduction in drain calls during heavy swap workloads.
 
 - The 3 patch series "mm: clean up folio LRU and swap declarations" from
   Jianyue Wu reorganizes folio LRU and swap code by relocating
   page-cluster state to mm/swap_state.c, renaming mm/swap.c to mm/folio.c,
   and moving MM-internal reclaim declarations into mm/internal.h.
 
 - The 15 patch series "userfaultfd: working set tracking for VM guest
   memory" from Kiryl Shutsemau adds userfaultfd support for tracking the
   working set of VM guest memory, so a VMM can identify hot pages and
   reclaim cold ones to tiered or remote storage.
 
 - The 10 patch series "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part
   2)" from David Hildenbrand removes the remaining pieces of
   CONFIG_HAVE_BOOTMEM_INFO_NODE, performing some smaller cleanups around
   freeing of reserved vmemmap pages on the way.
 
 - The 7 patch series "mm/damon: update probe hits for runtime parameter
   commits" from SJ Park ensures that DAMON's probe_hits attribute counter
   is properly updated when monitoring intervals are changed at runtime,
   matching the behavior of nr_accesses.  To achieve this, it refactors and
   renames existing helper functions for shared use, applies the updates to
   probe_hits, and handles edge cases in damon_probe_hits_mvsum() to
   maintain measurement accuracy.
 
 - The 3 patch series "KSM: performance optimizations for rmap_walk_ksm"
   from xu xin resolves a severe KSM reverse-mapping performance bottleneck
   where thousands of split VMAs sharing a single anon_vma cause extended
   lock contention.  By adding an interval-filtering check during the rmap
   walk, it reduces worst-case anon_vma lock hold times from over 500ms
   down to under 2ms, preventing application freezes and latency spikes
   under memory pressure.
 
 - The 3 patch series "mm: split a couple of headers from internal.h"
   from Mike Rapoport splits declarations related to mm_init, memblock,
   vmalloc and sparse into new headers.
 
 - The 2 patch series "KSM: use linear_page_index in collect_procs_ksm()"
   from xu xin applies the interval tree optimization from rmap_walk_ksm()
   to collect_procs_ksm() to avoid iterating over non-matching VMAs during
   KSM memory error handling.  It hoists loop-invariant address
   initialization and restricts the anon_vma_interval_tree_foreach walk to
   a targeted page offset range, reducing redundant checks and improving
   lookup efficiency.
 
 - The 3 patch series "selftests/mm: avoid false failures in hugetlb and
   KSM tests" from Sayali Patil fixes issues in the hugetlb and KSM MM
   selftest categories that can report failures when the prerequisites for
   the tests are not satisfied.
 
 - The 19 patch series "mm/damon: introduce data attributes only
   monitoring" from SJ Park introduces attribute-weighted region management
   in DAMON, allowing users to prioritize specific data attributes (such as
   page sizes or cgroups) over or instead of access monitoring.
 
   By assigning weights to attribute probes, DAMON can completely disable
   access tracking and adjust monitoring regions based on weighted
   probe-hit counters to optimize monitoring quality for attribute-focused
   workloads.
 
 - The 8 patch series "mm/hmm: Add mmap lock-drop support for
   userfaultfd-backed mappings" from Stanislav Kinsburskii extends
   hmm_range_fault() to support userfaultfd-backed regions by allowing the
   mmap lock to be dropped during fault handling via a new
   hmm_range_fault_locked() helper.
 
   By accepting a locked pointer and signaling retry status when lock
   release occurs, it enables page fault resolution in userfaultfd regions
   while preserving backward compatibility for existing callers.
 
 - The 33 patch series "mm: make VMA page offset handling more
   consistent" from Lorenzo Stoakes cleans up and standardizes how
   vma->vm_pgoff is accessed and manipulated across file-backed and
   anonymous mappings in the kernel.
 
   It introduces dedicated helper functions such as vma_start_pgoff(),
   vma_end_pgoff(), vma_set_pgoff() and linear_page_delta() while renaming
   rmap interval tree helpers to better reflect their functionality.
 
   These changes establish a cleaner foundation for future work that will
   unify virtual page offset indexing for all anonymous and CoW'd folios.
 
 - The 3 patch series "mm: handle device-private PMDs in walk callbacks"
   from Usama Arif addresses kernel panics and state corruption caused by
   MM walk callbacks reaching non-present device-private PMD swap entries
   created during HMM migrations.
 
   It ensures that functions which acquire pmd_trans_huge_lock() properly
   recognize device-private PMDs instead of assuming a present THP or a
   standard migration entry.
 
 - The 5 patch series "mm/rmap: Refactor try_to_unmap_one" from Dev Jain
   refactors try_to_unmap_one by modularizing Hugetlb, anonymous-lazyfree,
   and anonymous-swapbacked logic into dedicated functions, laying the
   structural groundwork for batched anonymous large folio unmapping.
 
 - The 4 patch series "Docs/ABI/damon: sysfs ABI document fixes and
   additions" from Song Hu fixes typos and fills in missing entries in the
   DAMON sysfs ABI document.
 
 - The 10 patch series "dax/kmem: atomic whole-device hotplug via sysfs"
   from Gregory Price introduces an atomic sysfs state attribute and
   supporting DAX/MM infrastructure to prevent userland races when
   offlining and removing entire memory regions.
 
   By adding an unplugged state alongside standard online modes, it
   enables whole-device atomic hotplug control while preserving backward
   compatibility.
 
 - The 13 patch series "mm: convert more vm_flags_t users to vma_flags_t"
   from Lorenzo Stoakes continues transitioning the kernel from the
   deprecated vm_flags_t type to vma_flags_t across core memory management
   infrastructure.
 
   It replaces legacy type usage in core functions such as do_mmap(),
   unmapped area allocation, mm->def_vma_flags, and VMA operations like
   mlock, mprotect, and mremap.
 
 - The 2 patch series "Two small patches to clean up mm/mm_slot.h" from
   xu xin refactors mm_slot.h by introducing mm_slot_remove() to unify
   duplicate slot deletion sequences in khugepaged and KSM.  It also adds
   code documentation explaining why mm_slot_lookup and mm_slot_insert must
   remain as preprocessor macros rather than static inline functions.
 
 - The 10 patch series "mm/damon/core: hide core-private struct fields"
   from SJ Park cleans up DAMON core structures by consistently marking
   internal-only fields with private: comment tags to prevent improper
   direct access from outer layers.
 
   It enforces encapsulation across core structures including
   damon_region, damon_target, and damon_ctx and updates DAMON_SYSFS to
   interact through approved access APIs instead of exposing raw struct
   members.
 
 - The 6 patch series "mm/damon: unurgent fixes for infinite loop, NULL
   de-ref and races" from SJ Park addresses potential infinite loops, NULL
   dereferences, and race conditions identified in DAMON.
 
   It fixes an infinite loop triggered by extreme user configurations, a
   NULL pointer dereference within unit tests and minor monitoring
   accuracy degradation caused by subtle runtime races.
 
 - The 2 patch series "mm/page_alloc: fixes for free_pages_nolock() on
   RT/UP" from Brendan Jackman fixes an NMI safety flaw in
   __free_frozen_pages() where freeing pages on non-SMP or PREEMPT_RT
   kernels can bypass can_spin_trylock() checks via non-PCP or isolated
   migration paths.
 
   It also resolves potential kernel crashes and privilege escalation
   risks triggered when BPF tracing runs in NMI context alongside memory
   hotplug or large allocation frees.
 
 - The 4 patch series "mm/page_alloc: couple of followups for recent
   cleanups" from Brendan Jackman cleans up and updates page allocator
   nomenclature, documentation, and debug assertions.
 
   It aligns internal FPI_ flags with the public "nolock" naming
   convention, removes outdated internal implementation details from
   high-level page allocator comments, and eliminates obsolete VM_BUG_ON()
   assertions in allocation paths.
 
 - The 3 patch series "mm/mseal: further cleanups" from Lorenzo Stoakes
   refactors and simplifies the mseal implementation by clarifying API
   boundaries and removing unnecessary code complexity.
 
   It replaces generic do_mseal() usage outside the syscall with a
   dedicated mseal_mmap_page_zero() helper for MMAP_PAGE_ZERO, eliminates
   mm_struct parameters to enforce that sealing applies only to
   current->mm, and streamlines overall logic and comments with no
   functional changes intended.
 
 - The 4 patch series "mm/vmscan: fix swappiness=max and clean up
   per-node proactive reclaim" from Ridong Chen resolves reclaim behavior
   bugs and cleans up function parameters across memory reclaim paths.
 
   It fixes swappiness=max in both standard reclaim and MGLRU so
   unswappable anonymous memory no longer falls back to evicting page
   cache, ensures reclaim_store() returns accurate error codes instead of
   collapsing all failures into -EAGAIN, and removes the obsolete gfp_mask
   parameter from __node_reclaim().
 
 - The 6 patch series "mm: mincore: misc cleanups" from Kefeng Wang
   cleans up and simplifies the mincore code.  Most importantly, it removes
   the historical special behavior that always reports VM_PFNMAP pages as
   non-resident.
 
 - The 2 patch series "mm/huge_memory: drop dead split helper variants"
   from Kiryl Shutsemau implements two trivial cleanups in the folio split
   API.
 
 - The 7 patch series "mm/damon: fix uninitialized DAMOS field and kunit
   exec expectation bugs" from SJ Park resolves minor operational and
   testing bugs in DAMON identified by Sashiko.  It initializes the
   damos->last_applied field to prevent occasional efficiency degradation
   and fixes invalid memory accesses in DAMON KUnit tests during test
   failure handling.
 
 - The 3 patch series "cleanup for stable_page_flags()" from Jinjiang Tu
   cleans up and refactors stable_page_flags() used by /proc/kpageflags
   without altering functionality.
 
   It uses BIT_ULL() to prevent shift-overflow warnings on 64-bit flag
   bits, converts folio-specific flag checks to standard folio_test_*()
   helpers, and removes redundant CONFIG_PAGE_IDLE_FLAG handling.
 
 - The 3 patch series "Batch unmap of uffd-wp file folios" from Dev Jain
   extends batched folio unmapping support to file folios within
   userfaultfd write-protect (uffd-wp) VMAs by adding batching capabilities
   to pte_install_uffd_wp_if_needed().
 
   This removes special-case restrictions on uffd-wp VMAs in
   try_to_unmap_one(), significantly simplifying the function's control
   flow and complexity.
 
 - The 3 patch series "mm/early_ioremap: clarify and clean up
   early_ioremap_reset()" from Sang-Heon Jeon clarifies and cleans up the
   architecture-specific usage of __late_set_fixmap() and
   __late_clear_fixmap() after early_ioremap_reset().
 
   It adds explicit documentation regarding when early_ioremap_reset()
   must be called and removes redundant macro definitions and reset calls
   in the RISC-V and ARM64 architectures.
 
 - The 4 patch series "mm: fix reclaim storms in defrag_mode" from
   Johannes Weiner addresses severe performance regressions, swap storms,
   and spurious OOMs caused by vm.defrag_mode=1 under high memory pressure
   in Meta production.
 
   It updates the page allocator slowpath so non-movable allocation
   requests actively trigger direct reclaim and direct compaction at
   pageblock_order scale, allowing them to claim whole pageblocks rather
   than spinning unproductively.
 
 - The 2 patch series "zram: lockmap tweaks" from Sebastian Siewior
   optimizes and fixes lockdep tracking for zram devices by consolidating
   per-entry lockmaps and isolating lock classes across multiple instances.
 
   It reduces memory overhead by replacing per-entry lockdep_map instances
   with a single map per struct zram, and assigns a dynamic lock_class_key
   to each instance to prevent false deadlock reports when different zram
   devices are backed by distinct filesystems.
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Merge tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - "mm: drop "sub" prefix from various places" (Dev Jain)

   page->folio conversion and a naming cleanup

 - "mm/kasan: remove redundant initialization for kasan_flag_write_only"
   (Igor Putko)

   KASAN cleanup work

 - "mm/filemap: reduce unnecessary xarray lookups" (Chi Zhiling)

   Small speedup in the pagecaache read code

 - "mm/percpu: Fix possible NOFS/NOIO reclaim recursion" (Kaitao Cheng)

   Improve the vmalloc code - mainly the avoidance of GFP_KERNEL
   allocations when the caller asked for GFP_NOFS or GFP_NOIO

 - "mm/kmemleak: avoid soft lockup when scanning task stacks" (Breno
   Leitao)

   Avoid a soft lockup watchdog trigger from the kmemleak scanning code
   in extreme situations

 - "mm/page_owner: misc cleanups" (Ye Liu)

   Cleanups to the page_owner code. For some reason lots of people have
   been working on the page_owner code this cycle.

 - "mm: convert to walk_page_range_vma() to eliminate find_vma()"
   (Kefeng Wang)

   Simplify and accelerate the page walking library function

 - "mm/migrate: preparatory cleanups for batch copy and offload"
   (Shivank Garg)

   Cleanups in the migration code

 - "mm/page_owner: add per-fd filter infrastructure for print_mode and
   NUMA filtering" (Zhen Ni)

   Per-fd filtering to page_owner in order to reduce the sometimes vast
   amount of output it can produce

 - "mm: Refactor bootmem gigantic hugepage allocation" (Muchun Song)

   Fixes and preparatory cleanups around bootmem HugeTLB handling,
   sparse initialization ordering, and related vmemmap setup

 - "mm/zsmalloc: reduce lock contention in zs_free()" (Wenchao Hao)

   Reduce lock contention in zs_free(), which dominates the unmap path
   under memory pressure on Android (LMK kills) and on x86 servers
   running zswap-heavy workloads.

   Up to 1.83x improvement in microbenchmarking.

 - "move alloc_tag.c file under mm/" (Suren Baghdasaryan)

 - "samples/damon: handle damon_{start,stop}() failures" (SJ Park)

   Fix improper handling of damon_start(), damon_stop(), and
   damon_call() failures across DAMON sample modules to prevent
   potential memory leaks, operation disruptions and use-after-free
   bugs

 - "mm/damon/sysfs: kobject_del() directories that users can
   create/remove" (SJ Park)

   Fix delayed sysfs directory removal under DEBUG_KOBJECT_RELEASE
   causeing creation failures due to duplicate directory names by adding
   missing kobject_del() calls before creating new directories

 - "mm: cleanup clear_not_present_full_ptes()" (David Hildenbrand)

   Clean up the core pte handling code

 - "selftests/damon: misc fixes for test bugs" (Kunwu Chan)

   Fix several bugs in the DAMON selftests

 - "selftests/damon: fix memcg_path staging handling" (Cheng Nie)

   Fix a bug in _damon_sysfs.py for damos_filter memcg_path setup, and
   add a test case for it in sysfs.py.

 - "selftests/damon: test kdamond refresh_ms" (Ruslan Valiyev)

   Selftest coverage for DAMON's refresh_ms sysfs feature by updating
   the test control module and verifying that scheme stats update
   automatically without manual intervention

 - "mm/damon: five misc fixups" (Akinobu Mita)

   Miscellaneous DAMON fixups.

 - "mm/damon/core: detect internal variation above max_nr_regions/2"
   (Jiayuan Chen)

   Fix DAMON's region splitting behavior when region counts exceed half
   the maximum budget by dynamically scaling down the split fraction as
   the limit approaches, preventing large regions from staying un-split,
   and add corresponding KUnit test coverage

 - "mm: preparatory patches for PMD level swap entries" (Usama Arif)

   Refactor and clean up PMD softleaf helpers, call sites, and
   architecture flags to lay the groundwork for a follow-up series that
   introduces PMD page table swap entries

 - "mm/damon: update, optimize, and clean up doc, tests, and code" (SJ
   Park)

   Update DAMON design and ABI documentation, expands unit and selftest
   coverage, optimize damon_commit_target_regions(), and clean up
   recently added sysfs interface code for better readability

 - "mm/vmpressure: reduce CPU, memory and code overhead on cgroup v2"
   (Usama Arif)

   Optimize vmpressure() by skipping unnecessary work on cgroup v2 for
   userspace event notifications and refactor v1-only eventfd handling
   into mm/memcontrol-v1.c to reduce memory overhead and code complexity

 - "selftests/mm: refactor pkey helpers and fix mmap error handling"
   (Hongfu Li)

   Refactor pkeys shared tracing and assertion helpers into a common
   file, unify protection key selftests to use consistent diagnostic
   logging and assertions, and enforce standardized MAP_FAILED return
   checks for mmap() calls across the tests

 - "mm/damon: optimize out nr_accesses_bp" (SJ Park)

   Replace the error-prone, continuously updated nr_accesses_bp field in
   damon_region with an on-demand moving sum function, reducing
   structure memory overhead and avoiding state corruption bugs

 - "Open HugeTLB allocation routine for more generic use" (Ackerley Tng)

   Decouple HugeTLB folio allocation from VMA dependencies by
   introducing hugetlb_alloc_folio(), enabling subsystems like
   guest_memfd to allocate HugeTLB folios without standard VMA
   reservations or pseudo-VMAs

 - "mm/damon: provide pseudo moving sum probe_hits" (SJ Park)

   Integrate DAMON's probe_hits attribute counter into the pseudo moving
   sum infrastructure, enabling real-time, online monitoring without
   waiting for full aggregation intervals

 - "mm: Some cleanups for page allocator APIs" (Brendan Jackman)

   Simplify and refactor the page allocator entry points and flags by
   unifying allocation paths, adding internal alloc_flags arguments, and
   eliminating redundant __ prefixed alloc_pages variants.

 - "Fix incorrect access of hugetlb pte entries" (Dev Jain)

   Enforce the consistent use of huge_ptep_get() instead of ptep_get()
   for HugeTLB entries and fixes an unaligned address issue in arm64's
   huge_ptep_get() implementation

 - "mm/damon: validate all parameters in the core" (SJ Park)

   Consolidate parameter validation into the DAMON core specifically
   within damon_start() and damon_commit_ctx() to centralize error
   checking, eliminate caller-side redundant checks and to improve
   maintenance efficiency

 - "tools/mm/page_owner_sort: fix filtering and cleanup issues" (Yichong
   Chen)

   Rename is_need() to filter_record() for clearer return semantics, fix
   per-record allocation memory leaks and bound output copies in
   search_pattern() to address an existing buffer issue

 - "memcg: bail out reclaim when memcg is dying" (Jiayuan Chen)

   Mitigate a system-wide stall which occurs when a cgroup is removed
   while one of its memory control files is doing synchronous reclaim

 - "mm/memory-failure: add panic option for unrecoverable pages" (Breno
   Leitao)

   Introduce an opt-in vm.panic_on_unrecoverable_memory_failure sysctl
   that immediately panics the kernel on unrecoverable memory errors in
   kernel-owned pages to preserve error context and prevent delayed,
   silent data corruption

 - "mm/damon: refactor damon_{start,stop,commit}() for simple error
   handling" (SJ Park)

   Refactor the DAMON core API functions to guarantee that all contexts
   are fully stopped when damon_start(), damon_stop(), or damon_commit()
   fail, eliminating the need for complex and error-prone caller-side
   cleanup code

 - "Keep tail page private zero at free and folio split" (Zi Yan)

   Add checks to ensure tail_page->private is zero when freeing compound
   or high-order pages and when promoting tail pages during large folio
   splits. By validating these fields at free and split time, it allows
   the removal of redundant private field clearing inside
   prep_compound_tail()

 - "mm: drop redundant lru_add_drain in anon folio reuse paths" (Barry
   Song)

   Eliminate redundant lru_add_drain() calls in
   wp_can_reuse_anon_folio() and do_swap_page() to reduce LRU lock
   contention and system overhead

   By validating folio refcounts against the LRU cache before draining
   and removing unnecessary drains in the swap path, it achieves up to a
   30.5% reduction in drain calls during heavy swap workloads

 - "mm: clean up folio LRU and swap declarations" (Jianyue Wu)

   Reorganize folio LRU and swap code by relocating page-cluster state
   to mm/swap_state.c, renaming mm/swap.c to mm/folio.c, and moving
   MM-internal reclaim declarations into mm/internal.h.

 - "userfaultfd: working set tracking for VM guest memory" (Kiryl
   Shutsemau)

   Add userfaultfd support for tracking the working set of VM guest
   memory, so a VMM can identify hot pages and reclaim cold ones to
   tiered or remote storage

 - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 2)" (David
   Hildenbrand)

   Remove the remaining pieces of CONFIG_HAVE_BOOTMEM_INFO_NODE,
   performing some smaller cleanups around freeing of reserved vmemmap
   pages on the way.

 - "mm/damon: update probe hits for runtime parameter commits" (SJ Park)

   Ensure that DAMON's probe_hits attribute counter is properly updated
   when monitoring intervals are changed at runtime, matching the
   behavior of nr_accesses. To achieve this, it refactors and renames
   existing helper functions for shared use, applies the updates to
   probe_hits, and handles edge cases in damon_probe_hits_mvsum() to
   maintain measurement accuracy.

 - "KSM: performance optimizations for rmap_walk_ksm" (xu xin)

   Resolve a severe KSM reverse-mapping performance bottleneck where
   thousands of split VMAs sharing a single anon_vma cause extended lock
   contention.

   By adding an interval-filtering check during the rmap walk, it
   reduces worst-case anon_vma lock hold times from over 500ms down to
   under 2ms, preventing application freezes and latency spikes under
   memory pressure.

 - "mm: split a couple of headers from internal.h" (Mike Rapoport)

   Split declarations related to mm_init, memblock, vmalloc and sparse
   into new headers

 - "KSM: use linear_page_index in collect_procs_ksm()" (xu xin)

   Apply the interval tree optimization from rmap_walk_ksm() to
   collect_procs_ksm() to avoid iterating over non-matching VMAs during
   KSM memory error handling.

   It hoists loop-invariant address initialization and restricts the
   anon_vma_interval_tree_foreach walk to a targeted page offset range,
   reducing redundant checks and improving lookup efficiency.

 - "selftests/mm: avoid false failures in hugetlb and KSM tests" (Sayali
   Patil)

   Fix issues in the hugetlb and KSM MM selftest categories that can
   report failures when the prerequisites for the tests are not
   satisfied

 - "mm/damon: introduce data attributes only monitoring" (SJ Park)

   Introduce attribute-weighted region management in DAMON, allowing
   users to prioritize specific data attributes (such as page sizes or
   cgroups) over or instead of access monitoring.

   By assigning weights to attribute probes, DAMON can completely
   disable access tracking and adjust monitoring regions based on
   weighted probe-hit counters to optimize monitoring quality for
   attribute-focused workloads.

 - "mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings"
   (Stanislav Kinsburskii)

   Extend hmm_range_fault() to support userfaultfd-backed regions by
   allowing the mmap lock to be dropped during fault handling via a new
   hmm_range_fault_locked() helper.

   By accepting a locked pointer and signaling retry status when lock
   release occurs, it enables page fault resolution in userfaultfd
   regions while preserving backward compatibility for existing callers.

 - "mm: make VMA page offset handling more consistent" (Lorenzo Stoakes)

   Clean up and standardize how vma->vm_pgoff is accessed and
   manipulated across file-backed and anonymous mappings in the kernel

   It introduces dedicated helper functions such as vma_start_pgoff(),
   vma_end_pgoff(), vma_set_pgoff() and linear_page_delta() while
   renaming rmap interval tree helpers to better reflect their
   functionality.

   These changes establish a cleaner foundation for future work that
   will unify virtual page offset indexing for all anonymous and CoW'd
   folios.

 - "mm: handle device-private PMDs in walk callbacks" (Usama Arif)

   Address kernel panics and state corruption caused by MM walk
   callbacks reaching non-present device-private PMD swap entries
   created during HMM migrations

   It ensures that functions which acquire pmd_trans_huge_lock()
   properly recognize device-private PMDs instead of assuming a present
   THP or a standard migration entry.

 - "mm/rmap: Refactor try_to_unmap_one" (Dev Jain)

   Refactor try_to_unmap_one by modularizing Hugetlb,
   anonymous-lazyfree, and anonymous-swapbacked logic into dedicated
   functions, laying the structural groundwork for batched anonymous
   large folio unmapping.

 - "Docs/ABI/damon: sysfs ABI document fixes and additions" (Song Hu)

   Fix typos and fills in missing entries in the DAMON sysfs ABI
   document

 - "dax/kmem: atomic whole-device hotplug via sysfs" (Gregory Price)

   Introduce an atomic sysfs state attribute and supporting DAX/MM
   infrastructure to prevent userland races when offlining and removing
   entire memory regions

   By adding an unplugged state alongside standard online modes, it
   enables whole-device atomic hotplug control while preserving backward
   compatibility.

 - "mm: convert more vm_flags_t users to vma_flags_t" (Lorenzo Stoakes)

   Continue transitioning the kernel from the deprecated vm_flags_t type
   to vma_flags_t across core memory management infrastructure.

   It replaces legacy type usage in core functions such as do_mmap(),
   unmapped area allocation, mm->def_vma_flags, and VMA operations like
   mlock, mprotect, and mremap.

 - "Two small patches to clean up mm/mm_slot.h" (xu xin)

   Refactor mm_slot.h by introducing mm_slot_remove() to unify duplicate
   slot deletion sequences in khugepaged and KSM. It also adds code
   documentation explaining why mm_slot_lookup and mm_slot_insert must
   remain as preprocessor macros rather than static inline functions.

 - "mm/damon/core: hide core-private struct fields" (SJ Park)

   Clean up DAMON core structures by consistently marking internal-only
   fields with private: comment tags to prevent improper direct access
   from outer layers.

   It enforces encapsulation across core structures including
   damon_region, damon_target, and damon_ctx and updates DAMON_SYSFS to
   interact through approved access APIs instead of exposing raw struct
   members.

 - "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races"
   (SJ Park)

   Address potential infinite loops, NULL dereferences, and race
   conditions identified in DAMON

   It fixes an infinite loop triggered by extreme user configurations, a
   NULL pointer dereference within unit tests and minor monitoring
   accuracy degradation caused by subtle runtime races.

 - "mm/page_alloc: fixes for free_pages_nolock() on RT/UP" (Brendan
   Jackman)

   Fix an NMI safety flaw in __free_frozen_pages() where freeing pages
   on non-SMP or PREEMPT_RT kernels can bypass can_spin_trylock() checks
   via non-PCP or isolated migration paths.

   It also resolves potential kernel crashes and privilege escalation
   risks triggered when BPF tracing runs in NMI context alongside memory
   hotplug or large allocation frees.

 - "mm/page_alloc: couple of followups for recent cleanups" (Brendan
   Jackman)

   Clean up and update page allocator nomenclature, documentation, and
   debug assertions.

   It aligns internal FPI_ flags with the public "nolock" naming
   convention, removes outdated internal implementation details from
   high-level page allocator comments, and eliminates obsolete
   VM_BUG_ON() assertions in allocation paths.

 - "mm/mseal: further cleanups" (Lorenzo Stoakes)

   Refactor and simplify the mseal implementation by clarifying API
   boundaries and removing unnecessary code complexity.

   It replaces generic do_mseal() usage outside the syscall with a
   dedicated mseal_mmap_page_zero() helper for MMAP_PAGE_ZERO,
   eliminates mm_struct parameters to enforce that sealing applies only
   to current->mm, and streamlines overall logic and comments with no
   functional changes intended.

 - "mm/vmscan: fix swappiness=max and clean up per-node proactive
   reclaim" (Ridong Chen)

   Resolve reclaim behavior bugs and clean up function parameters across
   memory reclaim paths

   It fixes swappiness=max in both standard reclaim and MGLRU so
   unswappable anonymous memory no longer falls back to evicting page
   cache, ensures reclaim_store() returns accurate error codes instead
   of collapsing all failures into -EAGAIN, and removes the obsolete
   gfp_mask parameter from __node_reclaim().

 - "mm: mincore: misc cleanups" (Kefeng Wang)

   Clean up and simplifies the mincore code. Most importantly, it
   removes the historical special behavior that always reports VM_PFNMAP
   pages as non-resident.

 - "mm/huge_memory: drop dead split helper variants" (Kiryl Shutsemau)

   Two trivial cleanups in the folio split API

 - "mm/damon: fix uninitialized DAMOS field and kunit exec expectation
   bugs" (SJ Park)

   Resolve minor operational and testing bugs in DAMON identified by
   Sashiko. It initializes the damos->last_applied field to prevent
   occasional efficiency degradation and fixes invalid memory accesses
   in DAMON KUnit tests during test failure handling.

 - "cleanup for stable_page_flags()" (Jinjiang Tu)

   Clean up and refactor stable_page_flags() used by /proc/kpageflags
   without altering functionality.

   It uses BIT_ULL() to prevent shift-overflow warnings on 64-bit flag
   bits, converts folio-specific flag checks to standard folio_test_*()
   helpers, and removes redundant CONFIG_PAGE_IDLE_FLAG handling.

 - "Batch unmap of uffd-wp file folios" (Dev Jain)

   Extend batched folio unmapping support to file folios within
   userfaultfd write-protect (uffd-wp) VMAs by adding batching
   capabilities to pte_install_uffd_wp_if_needed().

   This removes special-case restrictions on uffd-wp VMAs in
   try_to_unmap_one(), significantly simplifying the function's control
   flow and complexity.

 - "mm/early_ioremap: clarify and clean up early_ioremap_reset()"
   (Sang-Heon Jeon)

   Clarify and clean up the architecture-specific usage of
   __late_set_fixmap() and __late_clear_fixmap() after
   early_ioremap_reset()

   It adds explicit documentation regarding when early_ioremap_reset()
   must be called and removes redundant macro definitions and reset
   calls in the RISC-V and ARM64 architectures.

 - "mm: fix reclaim storms in defrag_mode" (Johannes Weiner)

   Address severe performance regressions, swap storms, and spurious
   OOMs caused by vm.defrag_mode=1 under high memory pressure in Meta
   production

   It updates the page allocator slowpath so non-movable allocation
   requests actively trigger direct reclaim and direct compaction at
   pageblock_order scale, allowing them to claim whole pageblocks rather
   than spinning unproductively.

 - "zram: lockmap tweaks" (Sebastian Siewior)

   Optimize and fix lockdep tracking for zram devices by consolidating
   per-entry lockmaps and isolate lock classes across multiple instances

   This reduces memory overhead by replacing per-entry lockdep_map
   instances with a single map per struct zram, and assigns a dynamic
   lock_class_key to each instance to prevent false deadlock reports
   when different zram devices are backed by distinct filesystems.

* tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (501 commits)
  selftests/mm: thuge-gen: fix test_shmget() for PAGE_SIZE check
  selftests/mm: unpoison pages in memory-failure teardown
  mm/shmem: downgrade final i_blocks check in shmem_evict_inode() to pr_warn()
  mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro
  mm/zsmalloc: fix release order of locks in zs_page_migrate()
  Documentation: zram: remove sections numbering
  ksm: stop iterating VMAs when ksm_test_exit returns true
  mm: fold userfaultfd_rwp() to false without CONFIG_ARCH_HAS_PTE_PROTNONE
  mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()
  zram: use a custom key for each zram object
  zram: move lockmap to be per-zram instead per table
  selftests/mm: fix gup_longterm EINVAL error message
  mm: page_alloc: fix non-movable reclaim storm in defrag_mode
  mm: page_alloc: move capture_control to the page allocator
  mm: compaction: support non-movable compaction for pageblock requests
  mm: page_alloc: __GFP_FS lockdep annotation for direct compaction
  hugetlb: evaluate subpool free state while locked
  mm/damon: remove trailing semicolons after function definitions
  mm/damon/ops-common: prevent migration fallback to non-target nodes
  mm/damon: update outdated comment about DAMOS filter handling
  ...
2026-08-20 18:17:08 -07:00
Linus Torvalds
6439079365 Probes updates for v7.3:
- probes: Advanced BTF typecasting and variable fetch enhancements
   . Typecast support across probe events: Extended BTF typecasting syntax
     (e.g., (STRUCT)PARAM->MEMBER) to kprobes, uprobes, and fprobes on
     function entry and return.
   . Nested typecasts: Added support for chaining and nesting typecasts up
     to 3 levels, including casting registers and stack variables.
   . Field specifier option: Added (STRUCT,FIELD) syntax to emulate
     container_of(), allowing retrieval of parent structures from member
     pointers.
   . $current variable support: Introduced $current special variable to
     access the running task_struct via BTF dereferencing.
   . Per-CPU variable access: Added this_cpu_read() and this_cpu_ptr()
     fetcharg methods to trace CPU-local data safely.
   . Fetcharg bytecode dumper: Added CONFIG_PROBE_EVENTS_DUMP_FETCHARG to
     dump the compiled fetcharg bytecode instructions as comments in
     dynamic_events.
   . Extended symbol name handling: Removed the MAX_COMMON_HEAD_LEN limit
     and extended MAX_ARGSTR_LEN to 256 bytes, enabling probing of long
     symbols, mangled Rust symbols and complex BTF expressions.
   . eprobe variable syntax: Allowed eprobes to reference event fields
     directly without requiring a '$' prefix.
   . Cleanup unused parameters, redundant codes, duplicate macros and
     pointer arithmetic.
   . Use a ternary operator for simplifying fetch_type_from_btf_type().
 
 - bootconfig / boottime-trace: Expanded dynamic probe support
   . Added boot-time tracing configuration support for event probes
     (eprobes), function probes (fprobes), and tracepoint probes
     (tprobes).
   . ftrace2bootconfig: Allowed comment lines ('#') in dynamic_events file.
 
 - fprobe / kprobe: Optimization, robustness, and cleanups
   . fprobe: Simplified fprobe_remove_ips() by reusing graph and ftrace
     helpers.
   . fprobe: Removed __packed attribute from struct __fprobe_header to avoid
     unaligned memory access penalties on RISC architectures.
   . kprobe & fprobe: Removed redundant memset() calls in perf event probe
     handlers.
   . kprobes: Replaced legacy __ASSEMBLY__ with __ASSEMBLER__ in header
     files.
 
 - selftests & refactoring:
   . Refactored parse_probe_arg() and parse_probe_vars(), and eliminated
     recursion in probe argument parsing to protect kernel stack depth.
   . Added selftests for BTF typecasts and module probing without module
     prefixes.
   . Forced LC_ALL=C in ftracetest to prevent test failures on localized
     systems.
   . Refactored btf_type_skip_modifiers() to remove ignored id parameter.
   . Sorted ERRORS list in trace_probe.h alphabetically.
   . Fixed typo in fprobe docs, and trace_fprobe function name.
   . Renamed FETCH_OP_DATA to FETCH_OP_IMMSTR.
   . Made file offset error message probe-agnostic.
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Merge tag 'probes-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:
 "BTF typecasting and variable fetch enhancements:

   - Typecast support across probe events: Extended BTF typecasting
     syntax (e.g., (STRUCT)PARAM->MEMBER) to kprobes, uprobes, and
     fprobes on function entry and return

   - Nested typecasts: Added support for chaining and nesting typecasts
     up to 3 levels, including casting registers and stack variables

   - Field specifier option: Added (STRUCT,FIELD) syntax to emulate
     container_of(), allowing retrieval of parent structures from member
     pointers

   - $current variable support: Introduced $current special variable to
     access the running task_struct via BTF dereferencing

   - Per-CPU variable access: Added this_cpu_read() and this_cpu_ptr()
     fetcharg methods to trace CPU-local data safely

   - Fetcharg bytecode dumper: Added CONFIG_PROBE_EVENTS_DUMP_FETCHARG
     to dump the compiled fetcharg bytecode instructions as comments in
     dynamic_events

   - Extended symbol name handling: Removed the MAX_COMMON_HEAD_LEN
     limit and extended MAX_ARGSTR_LEN to 256 bytes, enabling probing of
     long symbols, mangled Rust symbols and complex BTF expressions

   - eprobe variable syntax: Allowed eprobes to reference event fields
     directly without requiring a '$' prefix

   - Cleanup unused parameters, redundant codes, duplicate macros and
     pointer arithmetic

   - Use a ternary operator for simplifying fetch_type_from_btf_type()

  Expanded boot time dynamic probe support:

   - Add boot-time tracing configuration support for event probes
     (eprobes), function probes (fprobes), and tracepoint probes
     (tprobes)

   - Allow comment lines ('#') in dynamic_events file

  Optimization, robustness, and cleanups:

   - Simplify fprobe_remove_ips() by reusing graph and ftrace helpers

   - Remove __packed attribute from struct __fprobe_header to avoid
     unaligned memory access penalties on RISC architectures

   - Remove redundant memset() calls in perf event probe handlers

   - Replace legacy __ASSEMBLY__ with __ASSEMBLER__ in header files

  Selftests & refactoring:

   - Refactor parse_probe_arg() and parse_probe_vars(), and eliminate
     recursion in probe argument parsing to protect kernel stack depth

   - Add selftests for BTF typecasts and module probing without module
     prefixes

   - Force LC_ALL=C in ftracetest to prevent test failures on localized
     systems

   - Refactor btf_type_skip_modifiers() to remove ignored id parameter

   - Sort ERRORS list in trace_probe.h alphabetically

   - Fix typo in fprobe docs, and trace_fprobe function name

   - Rename FETCH_OP_DATA to FETCH_OP_IMMSTR

   - Make file offset error message probe-agnostic"

* tag 'probes-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (37 commits)
  fprobe: Simplify fprobe_remove_ips() by reusing existing helpers
  tracing/boot: Add support for eprobe, fprobe, and tprobe events
  selftests/ftrace: Force C locale in ftracetest
  tracing/probes: Treating longer symbol name on event comparation
  docs: trace: fprobe: fix 'thos' spelling
  tracing/probes: Fix extra whitespace in trace_probe_kernel.h
  tracing/kprobe: Remove redundant memset in kprobe_perf_func()
  tracing/fprobe: Remove redundant memset in fentry_perf_func()
  tracing/fprobe: Remove redundant snprintf in trace_fprobe_match_command_head()
  tracing/probes: Simplify BTF_KIND_PTR case in fetch_type_from_btf_type()
  tracing/probes: Cleanup pointer arithmetic in store_trace_entry_data()
  tracing/probes: Remove unused parameter from parse_probe_var_retval()
  tracing/probes: Remove redundant bounds check in trace_probe_compare_arg_type()
  tracing/probes: Remove redundant boolean conversion in trace_probe_has_single_file()
  tracing/probes: Remove duplicate MAX_ARRAY_LEN macro definition
  selftests/ftrace: Add test case for a symbol in a module without module name
  tracing/probes: Eliminate recursion in parse_probe_arg()
  tracing/probes: Extend max length of argument string
  tracing/probes: Sort ERRORS list in trace_probe.h alphabetically
  tracing/probes: Refactor parse_probe_arg()
  ...
2026-08-20 15:11:52 -07:00
Linus Torvalds
5a8cd539ac Major changes:
- Redesign the verifier error reporting: failures now carry source and
   instruction annotations along with the causal event history that led
   to them, making program rejections far easier to debug and repair
   (Kumar Kartikeya Dwivedi)
 
 - Add arena argument support to kfuncs and struct_ops through the new
   __arena and __arena__nullable suffixes (Tejun Heo, Puranjay Mohan,
   Kumar Kartikeya Dwivedi, Ihor Solodrai)
 
 - Signed BPF program loader rework to accommodate both BPF and security
   community needs where the kernel runs the signature verification at
   BPF_PROG_LOAD time before the LSM admission hook (Daniel Borkmann)
 
 - Add a set of ksock kfuncs which let BPF LSM and syscall programs
   create, connect and send on UDP sockets in order to emit telemetry
   data (Mahe Tardy)
 
 - Unify helper and kfunc call argument verification and classify kfunc
   arguments purely from BTF into a generated bpf_func_proto which is
   computed once at add-call time (Amery Hung)
 
 Other features and fixes:
 
 - Enable EXECMEM_ROX_CACHE for BPF allocations on x86 (Mike Rapoport)
 
 - Add bidirectional VLAN support to bpf_fib_lookup() through the new
   BPF_FIB_LOOKUP_VLAN and BPF_FIB_LOOKUP_VLAN_INPUT flags
   (Avinash Duduskar)
 
 - Infer zext_dst from static register liveness analysis to fix 32-bit
   zero-extension semantics, and remove the artificial limitations on
   pointer types eligible for spilling (Eduard Zingerman)
 
 - Inline the numeric open-coded iterator kfuncs so that bpf_for() loops
   no longer pay a kfunc call on every iteration (Puranjay Mohan)
 
 - Add an arena-based bitmap data structure to libarena along with
   serial and parallel selftests (Emil Tsalapatis)
 
 - Teach resolve_btfids to discover kfuncs from the kernel's BTF ID sets
   and to emit kfunc BTF decl tags, reducing the kernel build's
   dependency on pahole features (Ihor Solodrai)
 
 - Add BPF_F_ADJ_ROOM_DECAP_* flags to bpf_skb_adjust_room() so that
   tunnel decapsulation can update the GSO and encapsulation state of
   the skb (Nick Hudson)
 
 - Fix the ring buffer pending_pos walk and the available-data
   accounting on 32-bit position wrap (Israel Téllez García)
 
 - Add memory usage accounting for arena maps and fix an mmap_lock
   deadlock on arena lock failure (Jiayuan Chen)
 
 - Add tracing_multi link info support to the kernel UAPI and bpftool,
   and refactor the stack map code to run with preemption disabled
   (Jiri Olsa)
 
 - Support BPF_F_EGRESS in bpf_redirect_peer() to emit the skb in the
   egress direction of the target's peer device (Jordan Rife)
 
 - Add a KF_SPINLOCK_SAFE kfunc flag so that providers, in particular
   modules, can declare kfuncs safe to call under bpf_spin_lock instead
   of relying on the verifier's hard-coded allowlist (Kaitao Cheng)
 
 - Introduce global percpu data for BPF programs with libbpf probing
   and bpftool skeleton support, and stop exposing uninitialized kernel
   heap memory when copying per-CPU map values (Leon Hwang)
 
 - Add s390 JIT support for load-acquire and store-release instructions
   (Maxim Khmelevskii)
 
 - Fix a CFI mismatch in the task work callback and an arm64 KASAN
   false positive after bpf_throw() (Mykyta Yatsenko)
 
 - Reject writes through untrusted BTF pointers and bound the
   rdonly/rdwr_buf_size kfunc arguments (Nicholas Dudar)
 
 - Invalidate RCU pointers only after the final spin unlock and account
   for preempt and IRQ disabled regions as overlapping RCU protection
   (Ning Ding)
 
 - Support mixing bpf2bpf calls and tail calls on RV64, add signed
   operations and 32-bit atomics to the RV32 JIT, and add timed may_goto
   support (Pu Lehui, Kuan-Wei Chiu, Feng Jiang)
 
 - Fix a use-after-free on mm_struct in bpf_find_vma() for foreign tasks
   and an mmap_lock leak in the irq_work path (Sanghyun Park)
 
 - Populate mmap-able BPF array map memory lazily which makes mmap() O(1)
   instead of proportional to the map size (Song Liu)
 
 - Introduce a jit_required flag and reject programs with inlined
   helpers when no JIT is available, where the interpreter would
   otherwise jump into an invalid address (Tiezhu Yang)
 
 - Fix the x86 JIT per-CPU address resolution into an extended register
   where the REX prefix dropped the high destination register bit
   (Vineet Gupta)
 
 - Reject MEM_ALLOC BTF accesses past object bounds, arena frees below
   the arena base, and mixed arena and ordinary atomic paths
   (Yiyang Chen)
 
 - Fix the trampoline handling of 128-bit arguments and of return values
   larger than 8 bytes (Yonghong Song)
 
 - Ensure that any fault prone load is rewritten with exception table
   handling, and fix the arena load-acquire and atomic fetch handling
   in the x86, arm64, riscv and s390 JITs (Daniel Borkmann)
 
 - Many more fixes and cleanups across the verifier, arena, trampolines,
   sockmap, cgroup, ring buffer, x86/arm64/riscv/s390 JITs, libbpf,
   bpftool, resolve_btfids and selftests.
 
 Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Merge tag 'bpf-next-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Pull bpf updates from Daniel Borkmann:
 "Major changes:

   - Redesign the verifier error reporting: failures now carry source
     and instruction annotations along with the causal event history
     that led to them, making program rejections far easier to debug and
     repair (Kumar Kartikeya Dwivedi)

   - Add arena argument support to kfuncs and struct_ops through the new
     __arena and __arena__nullable suffixes (Tejun Heo, Puranjay Mohan,
     Kumar Kartikeya Dwivedi, Ihor Solodrai)

   - Signed BPF program loader rework to accommodate both BPF and
     security community needs where the kernel runs the signature
     verification at BPF_PROG_LOAD time before the LSM admission hook
     (Daniel Borkmann)

   - Add a set of ksock kfuncs which let BPF LSM and syscall programs
     create, connect and send on UDP sockets in order to emit telemetry
     data (Mahe Tardy)

   - Unify helper and kfunc call argument verification and classify
     kfunc arguments purely from BTF into a generated bpf_func_proto
     which is computed once at add-call time (Amery Hung)

  Other features and fixes:

   - Enable EXECMEM_ROX_CACHE for BPF allocations on x86 (Mike Rapoport)

   - Add bidirectional VLAN support to bpf_fib_lookup() through the new
     BPF_FIB_LOOKUP_VLAN and BPF_FIB_LOOKUP_VLAN_INPUT flags (Avinash
     Duduskar)

   - Infer zext_dst from static register liveness analysis to fix 32-bit
     zero-extension semantics, and remove the artificial limitations on
     pointer types eligible for spilling (Eduard Zingerman)

   - Inline the numeric open-coded iterator kfuncs so that bpf_for()
     loops no longer pay a kfunc call on every iteration (Puranjay
     Mohan)

   - Add an arena-based bitmap data structure to libarena along with
     serial and parallel selftests (Emil Tsalapatis)

   - Teach resolve_btfids to discover kfuncs from the kernel's BTF ID
     sets and to emit kfunc BTF decl tags, reducing the kernel build's
     dependency on pahole features (Ihor Solodrai)

   - Add BPF_F_ADJ_ROOM_DECAP_* flags to bpf_skb_adjust_room() so that
     tunnel decapsulation can update the GSO and encapsulation state of
     the skb (Nick Hudson)

   - Fix the ring buffer pending_pos walk and the available-data
     accounting on 32-bit position wrap (Israel Téllez García)

   - Add memory usage accounting for arena maps and fix an mmap_lock
     deadlock on arena lock failure (Jiayuan Chen)

   - Add tracing_multi link info support to the kernel UAPI and bpftool,
     and refactor the stack map code to run with preemption disabled
     (Jiri Olsa)

   - Support BPF_F_EGRESS in bpf_redirect_peer() to emit the skb in the
     egress direction of the target's peer device (Jordan Rife)

   - Add a KF_SPINLOCK_SAFE kfunc flag so that providers, in particular
     modules, can declare kfuncs safe to call under bpf_spin_lock
     instead of relying on the verifier's hard-coded allowlist (Kaitao
     Cheng)

   - Introduce global percpu data for BPF programs with libbpf probing
     and bpftool skeleton support, and stop exposing uninitialized
     kernel heap memory when copying per-CPU map values (Leon Hwang)

   - Add s390 JIT support for load-acquire and store-release
     instructions (Maxim Khmelevskii)

   - Fix a CFI mismatch in the task work callback and an arm64 KASAN
     false positive after bpf_throw() (Mykyta Yatsenko)

   - Reject writes through untrusted BTF pointers and bound the
     rdonly/rdwr_buf_size kfunc arguments (Nicholas Dudar)

   - Invalidate RCU pointers only after the final spin unlock and
     account for preempt and IRQ disabled regions as overlapping RCU
     protection (Ning Ding)

   - Support mixing bpf2bpf calls and tail calls on RV64, add signed
     operations and 32-bit atomics to the RV32 JIT, and add timed
     may_goto support (Pu Lehui, Kuan-Wei Chiu, Feng Jiang)

   - Fix a use-after-free on mm_struct in bpf_find_vma() for foreign
     tasks and an mmap_lock leak in the irq_work path (Sanghyun Park)

   - Populate mmap-able BPF array map memory lazily which makes mmap()
     O(1) instead of proportional to the map size (Song Liu)

   - Introduce a jit_required flag and reject programs with inlined
     helpers when no JIT is available, where the interpreter would
     otherwise jump into an invalid address (Tiezhu Yang)

   - Fix the x86 JIT per-CPU address resolution into an extended
     register where the REX prefix dropped the high destination register
     bit (Vineet Gupta)

   - Reject MEM_ALLOC BTF accesses past object bounds, arena frees below
     the arena base, and mixed arena and ordinary atomic paths (Yiyang
     Chen)

   - Fix the trampoline handling of 128-bit arguments and of return
     values larger than 8 bytes (Yonghong Song)

   - Ensure that any fault prone load is rewritten with exception table
     handling, and fix the arena load-acquire and atomic fetch handling
     in the x86, arm64, riscv and s390 JITs (Daniel Borkmann)

   - Many more fixes and cleanups across the verifier, arena,
     trampolines, sockmap, cgroup, ring buffer, x86/arm64/riscv/s390
     JITs, libbpf, bpftool, resolve_btfids and selftests"

* tag 'bpf-next-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (373 commits)
  selftests/bpf: Add tests for a store on a fault prone qdisc pointer
  selftests/bpf: Add tests for fault prone loads out of RCU pointers
  selftests/bpf: Add tests for pointer type merge at a shared load
  selftests/bpf: Remove duplicate copies of the arena spinlock qnodes
  selftests/bpf: Retry stat generation in cgroup_iter_memcg
  selftests/bpf: Test pseudo-function policy diagnostics
  bpf: Distinguish function references in policy diagnostics
  bpf: Preserve source attribution without source text
  selftests/bpf: Test kfunc argument diagnostics
  bpf: Correct kfunc argument diagnostics
  bpf: Use canonical stack argument names in diagnostics
  bpf: Preserve R0 lineage across helper calls
  selftests/bpf: Exercise negative optlen in cgroup getsockopt hook
  bpf: Reject negative optlen in cgroup getsockopt hook
  selftests/bpf: tc_tunnel - validate decap GSO and encapsulation state
  bpf: Clear decap state on skb_adjust_room shrink path
  bpf: Allow new DECAP flags and add guard rails
  bpf: Add BPF_F_ADJ_ROOM_DECAP_* flags for tunnel decapsulation
  bpf: Refactor masks for ADJ_ROOM flags and encap validation
  bpf: Name the enum for BPF_FUNC_skb_adjust_room flags
  ...
2026-08-20 07:36:20 -07:00
Linus Torvalds
cb8a75eec0 ring-buffer updates for 7.3:
- Remove unneeded semicolon
 
   A macro ended with a semicolon that wasn't needed.
 
 - Fix freeing cpu_buffer extra subbuffer with order greater than zero
 
   When the cpu_buffer was being freed, its "free" page, was using
   free_page() to free it when it could be more than one page.
 
 - Hold the cpu_buffer lock when resizing the subbuffer
 
   The freeing of the "free" page of the cpu_buffer was done without locking.
   The order of the data was being saved and then the "free" page was set to
   NULL. But there is a race that the "free" page could have been updated
   between those two operations. Add locking around it to prevent the race.
 
 - Save the order of the data along with the data in the free page
 
   The cpu_buffer would store just the data portion of the subbuffer page in
   its descriptor. But it did not store the order of the data pages. The order
   was being saved in the global buffer descriptor. But this leads to races.
 
   Have the cpu_buffer save the subbuf data along with its metadata (which
   includes the order of the page) to make sure when it frees it, it frees
   the correct order along with it.
 
 - Remove the subbuf_size and use the order directly when needed
 
   Having a size field for the size of the subbufer along with its order
   allowed for races to have them get out of sync. Remove the subbuf_size and
   use the order from the subbuf meta data directly under locks.
 
   Use the subbuf_order for other calculations in the ring buffer.
 
 - Remove the useless "cpus" field of trace_buffer
 
   The code has been restructured and the "cpus" field is no longer used.
   Remove it.
 
 - Remove the "mapped" field of the ring buffer and use a helper function instead.
 
   The "mapped" field has become a bit overused and made the code come
   complex in using a counter for what is denoted as being mapped or not.
   There are other fields that are set when the ring buffer is considered
   mapped. Add a helper function to check those fields and use that instead
   of keeping track of a counter.
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Merge tag 'trace-ringbuffer-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ring-buffer updates from Steven Rostedt:

 - Remove unneeded semicolon

   A macro ended with a semicolon that wasn't needed.

 - Fix freeing cpu_buffer extra subbuffer with order greater than zero

   When the cpu_buffer was being freed, its "free" page, was using
   free_page() to free it when it could be more than one page.

 - Hold the cpu_buffer lock when resizing the subbuffer

   The freeing of the "free" page of the cpu_buffer was done without
   locking. The order of the data was being saved and then the "free"
   page was set to NULL. But there is a race that the "free" page could
   have been updated between those two operations. Add locking around it
   to prevent the race.

 - Save the order of the data along with the data in the free page

   The cpu_buffer would store just the data portion of the subbuffer
   page in its descriptor. But it did not store the order of the data
   pages. The order was being saved in the global buffer descriptor. But
   this leads to races.

   Have the cpu_buffer save the subbuf data along with its metadata
   (which includes the order of the page) to make sure when it frees it,
   it frees the correct order along with it.

 - Remove the subbuf_size and use the order directly when needed

   Having a size field for the size of the subbufer along with its order
   allowed for races to have them get out of sync. Remove the
   subbuf_size and use the order from the subbuf meta data directly
   under locks.

   Use the subbuf_order for other calculations in the ring buffer.

 - Remove the useless "cpus" field of trace_buffer

   The code has been restructured and the "cpus" field is no longer
   used. Remove it.

 - Remove the "mapped" field of the ring buffer and use a helper
   function instead.

   The "mapped" field has become a bit overused and made the code come
   complex in using a counter for what is denoted as being mapped or
   not. There are other fields that are set when the ring buffer is
   considered mapped. Add a helper function to check those fields and
   use that instead of keeping track of a counter.

* tag 'trace-ringbuffer-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Remove ring_buffer_per_cpu::mapped
  ring-buffer: Remove trace_buffer::cpus
  ring-buffer: Dynamically calculate max_data_size
  ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()
  ring-buffer: Fix subbuf resize race with ring buffer readers
  ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
  ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
  ring-buffer: Free cpu_buffer::free_page with subbuf_order
  ring-buffer: drop unneeded semicolon
2026-08-19 14:22:07 -07:00
Linus Torvalds
1484625c59 tracefs updates for v7.3:
- Define event fields before directory creation
 
   Move the event_define_fields() call in event_create_dir() before the
   eventfs directory creation. Previously, a failure after directory
   creation wouldn't clean up eventfs_inode because the error path didn't
   call eventfs_remove_dir(). This eliminates the need to clean up the
   eventfs directories if event_define_fields() fails.
 
 - Add warning for out of bounds pos in __eventfs_iterate()
 
   Sashiko complains about the ctx->pos causing issues if it is less than 2
   or greater than MAX_INT in __eventfs_iterate(). The thing is, the logic
   prevents that from happening. But to make Sashiko happy, add a WARN_ON()
   and exit safely if the function ever does get input that is out of the
   range the function expects.
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Merge tag 'tracefs-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracefs updates from Steven Rostedt:

 - Define event fields before directory creation

   Move the event_define_fields() call in event_create_dir() before the
   eventfs directory creation. Previously, a failure after directory
   creation wouldn't clean up eventfs_inode because the error path
   didn't call eventfs_remove_dir(). This eliminates the need to clean
   up the eventfs directories if event_define_fields() fails.

 - Add warning for out of bounds pos in __eventfs_iterate()

   Sashiko complains about the ctx->pos causing issues if it is less
   than 2 or greater than MAX_INT in __eventfs_iterate(). The thing is,
   the logic prevents that from happening. But to make Sashiko happy,
   add a WARN_ON() and exit safely if the function ever does get input
   that is out of the range the function expects.

* tag 'tracefs-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  eventfs: Add warning for out of bounds pos in __eventfs_iterate()
  eventfs: Define event fields before directory creation
2026-08-19 14:18:45 -07:00
Linus Torvalds
081e5bf2a9 tracing updates for v7.3:
- Expose btf_ids to trace events
 
   In order to allow BPF programs to attach to system call trace events (which
   are actually pseudo trace events built on top of raw_syscall events),
   expose the BTF ID of the events. This will allow BPF programs better
   precision in attaching to events.
 
 - Use "u64" to assign to hist_field->type
 
   Instead of using kstrdup("u64", GFP_KERNEL) to assign the hist_field->type,
   just point it to "u64" instead. The hist_field->type is freed via
   kfree_const().
 
 - Replace kmalloc()/strcpy() with kstrdup() for trace_printk
 
   Instead of having two calls to copy the module format string, just use
   kstrdup().
 
 - Use __free() in trace event histograms and triggres where possible
 
 - Use seq_buf in trace event code instead of strcat()
 
   Instead of calculating the size of the buffer to use and filling it with
   strcat(), use the seq_buf infrastructure that takes care of making sure
   not to overflow the string size.
 
 - Reject invalid preemptirq_delay_test CPU affinity
 
   The preempt_delay_test module can take an invalid CPU affinity mask and
   create confusing output. Simply have the module reject invalid affinity
   masks.
 
 - Prevent division by zero in ftrace_ops sample module code
 
   If the ftrace_ops sample module code receives the module parameter
   nr_function_calls set to zero, it can cause a division by zero error.
 
 - Warn when an event dereferences a parameter in TP_printk()
 
   On boot up and module load, the trace event TP_printk() is scanned for
   possible bugs. As the TP_printk() code is executed when the user reads the
   "trace" file and processes the data written when the trace_event executed,
   the data it reads can be literally days old. The scan currently checks for
   dereferencing printk formats like "%pI6". But it does not check if the
   parameters themselves have a dereference like:
 
   TP_printk("offset %08x: value %08x",
            (u32)(__entry->addr - __entry->edma->membase), __entry->value)
 
   __entry represents the pointer to the event on the ring buffer. The
   __entry->edma->membase is dereferencing a pointer on the ring buffer to
   find membase, but the __entry->edma may no longer be a valid pointer.
 
   Warn on this case too.
 
 - Replace some strcpy() with strscpy()
 
 - Clean up mmiotrace events to use assign_type() macro
 
   The assign_type() macro makes sure the event type is indeed the type that
   is being parsed. The mmiotrace trace was written before that macro was
   created so it just simply typecasted the pointer.
 
   Replace the typecasting with the macro.
 
 - Have the ENUM processing to numbers only process what is added
 
   The code that converts ENUMs to their numbers in the trace events scanned
   all events to do the processing. This was true when a module was loaded
   too. That is, instead of processing just the events for the module, it
   processed *all* events. Even the builtin ones that were processed at boot
   up.
 
   Add a check for the event->module matching mod if it is a module before
   processing it.
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Merge tag 'trace-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Expose btf_ids to trace events

   In order to allow BPF programs to attach to system call trace events
   (which are actually pseudo trace events built on top of raw_syscall
   events), expose the BTF ID of the events. This will allow BPF
   programs better precision in attaching to events.

 - Use "u64" to assign to hist_field->type

   Instead of using kstrdup("u64", GFP_KERNEL) to assign the
   hist_field->type, just point it to "u64" instead. The
   hist_field->type is freed via kfree_const().

 - Replace kmalloc()/strcpy() with kstrdup() for trace_printk

   Instead of having two calls to copy the module format string, just
   use kstrdup().

 - Use __free() in trace event histograms and triggres where possible

 - Use seq_buf in trace event code instead of strcat()

   Instead of calculating the size of the buffer to use and filling it
   with strcat(), use the seq_buf infrastructure that takes care of
   making sure not to overflow the string size.

 - Reject invalid preemptirq_delay_test CPU affinity

   The preempt_delay_test module can take an invalid CPU affinity mask
   and create confusing output. Simply have the module reject invalid
   affinity masks.

 - Prevent division by zero in ftrace_ops sample module code

   If the ftrace_ops sample module code receives the module parameter
   nr_function_calls set to zero, it can cause a division by zero error.

 - Warn when an event dereferences a parameter in TP_printk()

   On boot up and module load, the trace event TP_printk() is scanned
   for possible bugs. As the TP_printk() code is executed when the user
   reads the "trace" file and processes the data written when the
   trace_event executed, the data it reads can be literally days old.
   The scan currently checks for dereferencing printk formats like
   "%pI6". But it does not check if the parameters themselves have a
   dereference like:

	TP_printk("offset %08x: value %08x",
		(u32)(__entry->addr - __entry->edma->membase), __entry->value)

   __entry represents the pointer to the event on the ring buffer. The
   __entry->edma->membase is dereferencing a pointer on the ring buffer
   to find membase, but the __entry->edma may no longer be a valid
   pointer.

   Warn on this case too.

 - Replace some strcpy() with strscpy()

 - Clean up mmiotrace events to use assign_type() macro

   The assign_type() macro makes sure the event type is indeed the type
   that is being parsed. The mmiotrace trace was written before that
   macro was created so it just simply typecasted the pointer.

   Replace the typecasting with the macro.

 - Have the ENUM processing to numbers only process what is added

   The code that converts ENUMs to their numbers in the trace events
   scanned all events to do the processing. This was true when a module
   was loaded too. That is, instead of processing just the events for
   the module, it processed *all* events. Even the builtin ones that
   were processed at boot up.

   Add a check for the event->module matching mod if it is a module
   before processing it.

* tag 'trace-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (21 commits)
  tracing: Have trace_event_update_all() only handle module that is loading
  tracing: Cleanup event_enable_trigger_parse() by using __free()
  tracing: Report every TP_printk double dereference
  tracing/mmiotrace: Use trace_assign_type() in mmio_print_mark()
  tracing: Make per-template BTF id lists file-local
  tracing: Use seq_buf for string concatenation
  tracing: Use strscpy() instead of strcpy() in trace_sched_switch
  tracing: Warn when an event dereferences a pointer in TP_printk()
  samples/ftrace: Prevent division by zero when nr_function_calls is zero
  tracing: Reject invalid preemptirq_delay_test CPU affinity
  fgraph: Use trace_seq_putc() in print_graph_return()
  tracing/user_events: Replace a seq_printf() call by seq_puts() in user_seq_show()
  tracing/user_events: Use seq_putc() in two functions
  tracing: Bound histogram expression strings with seq_buf
  tracing: Return ERR_PTR() from expr_str()
  tracing: Use __free() for expr_str() buffer
  kernel/trace/trace_printk: Use kstrdup() instead of kmalloc() and strcpy()
  tracing: Point constant hist field type to string literal
  selftests/bpf: Add test for tracepoint btf_ids tracefs file
  tracing: Expose tracepoint BTF ids via tracefs
  ...
2026-08-19 14:06:14 -07:00
Linus Torvalds
00d66b29a6 ftrace updates for 7.3:
- Deprecrate ftrace_enabled in disabling ftrace
 
   The file /proc/sys/kernel/ftrace_enabled was created when ftrace was first
   introduced back in 2008. It was to be a "kill switch" if something was to
   go wrong. It was also used as a way to turn off function tracing for the
   latency tracers that would have it on by default. But in 2013 (Linux 3.10)
   the option "function-trace" was introduced to disable function tracing for
   the latency tracers as the "ftrace_enabled" file was considered too big of
   a hammer and caused too many side effects.
 
   When live kernel patching came along, disabling ftrace via the
   ftrace_enabled file would put the system into an unstable state if a live
   kernel patch was installed. This created the need to mark some function
   hooks as "PERMANENT".
 
   Now there's a need for BPF usage marked as PERMANENT for the same reasons.
 
   The file "ftrace_enabled" usage is no longer viable. It doesn't do what it
   says it does and there is no reason to use it.
 
   Make writing '0' to it a nop and print a message saying its usage is
   deprecated. The return value of writing '0' is -EOPNOTSUPP so that user
   space will error on that write (hopefully to inform any developer that it
   no longer works).
 
   Eventually the file should be removed completely, but for now just making
   it not do anything is the path forward to that.
 
 - Update the livepatch tests to handle ftrace_enabled being disabled
 
   Because in the past, livepatch was broken by ftrace_enabled being turned
   off, there's a test case that checks to make sure it still doesn't break.
   But having the write of '0' return an error caused that test to break.
   Updated the test to handle the new change.
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Merge tag 'ftrace-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace updates from Steven Rostedt:

 - Deprecrate ftrace_enabled in disabling ftrace

   The file /proc/sys/kernel/ftrace_enabled was created when ftrace was
   first introduced back in 2008. It was to be a "kill switch" if
   something was to go wrong. It was also used as a way to turn off
   function tracing for the latency tracers that would have it on by
   default. But in 2013 (Linux 3.10) the option "function-trace" was
   introduced to disable function tracing for the latency tracers as the
   "ftrace_enabled" file was considered too big of a hammer and caused
   too many side effects.

   When live kernel patching came along, disabling ftrace via the
   ftrace_enabled file would put the system into an unstable state if a
   live kernel patch was installed. This created the need to mark some
   function hooks as "PERMANENT".

   Now there's a need for BPF usage marked as PERMANENT for the same
   reasons.

   The file "ftrace_enabled" usage is no longer viable. It doesn't do
   what it says it does and there is no reason to use it.

   Make writing '0' to it a nop and print a message saying its usage is
   deprecated. The return value of writing '0' is -EOPNOTSUPP so that
   user space will error on that write (hopefully to inform any
   developer that it no longer works).

   Eventually the file should be removed completely, but for now just
   making it not do anything is the path forward to that.

 - Update the livepatch tests to handle ftrace_enabled being disabled

   Because in the past, livepatch was broken by ftrace_enabled being
   turned off, there's a test case that checks to make sure it still
   doesn't break. But having the write of '0' return an error caused
   that test to break. Updated the test to handle the new change.

* tag 'ftrace-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  selftests/livepatch: update test-ftrace.sh for deprecated ftrace_enabled
  ftrace: deprecate disabling via ftrace_enabled sysctl
2026-08-19 14:01:58 -07:00
Linus Torvalds
55ee4b931a Real-time Verifier updates for v7.3
- Switch LTL and DOT parsers to Lark in code generation tool
 
   The rvgen code generation tool originally parsed DOT files and LTL
   specifications using custom string parsing and Ply, which is no longer
   maintained. The DOT parser was fragile and prone to failure on minor
   format variations. Both LTL and DOT parsers have been rewritten to use
   the Lark parsing library.
 
 - Simplify Hybrid Automata clock variables
 
   The clock variables in hybrid automata monitors now use a single
   representation of the elapsed time since the clock was reset, rather
   than converting between invariant and guard representations.
   This allows simpler code generation for the newly refactored parser.
 
 - Generate cleanup hook for per-obj monitor
 
   The code generation scripts now adds a cleanup function to per-obj
   monitors for the user to wire to the appropriate event (e.g.
   sched_process_exit for tasks).
 
 - Reduce read_lock scope during per-task cleanup
 
   Take the tasklist_lock only when necessary, that is when iterating
   over for_each_process_thread().
 
 - Simplify task monitor slot management
 
   Only rely on the slot array for per-task slot management to avoid
   inconsistency with the unused counter.
 
 - Improve rvgen code robustness and templates
 
   Use pathlib in rvgen and improve kernel path discovery. Also improve
   consistency across templates when generating code (e.g. author
   placeholder and monitor struct name).
 
 - Update rtapp sleep monitor
 
   Simplify the sleep monitor by excluding kernel threads and
   updating the nanosleep check to focus only on CLOCK_REALTIME. Also
   switch to use the sched_exit tracepoint to run in the context of the
   offending (wakee) task.
 
 - Add wakeup monitor
 
   Add the new rtapp/wakeup monitor to detect when lower-priority tasks
   wake up higher-priority ones, complementing the existing sleep monitor
   by running in the waker context and capturing its stack trace.
 
 - Fix tools/rv exit status on failure
 
   Ensure the rv tool returns a failure exit code when a monitor fails to
   start because it was already running.
 
 - Add automated selftests for tools/rv and rvgen
 
   Introduced automated bash selftests to validate rv monitor listing and
   execution under different configurations. Added tests for the rvgen code
   generator, validating generated files against expected output (golden).
   Tests are reachable via make check.
 
 - Add KUnit test coverage for verification monitors
 
   Added comprehensive KUnit tests to validate the functionality of
   deterministic, hybrid, and LTL monitors by emulating event sequences
   and timing in a mock environment without affecting the running kernel
   while expecting mock reactions to fire. Ensure real RV monitors cannot
   run during KUnit tests to avoid state corruption.
 
 - Mock current in rv monitors
 
   Mock the call to current in rv monitors when the KUnit tests are built
   to allow them to run the test on dummy tasks. No overhead is expected
   when KUnit tests aren't running.
 
 - Introduce rvgen kunit subcommand
 
   Added a new 'kunit' subcommand to rvgen to automatically patch an already
   generated monitor with KUnit integration templates by parsing its event
   handlers and creating the required mock structures and initializations.
 
 - Refine kernel verification selftests
 
   Added new selftests for the deadline and stall monitors and rearranged
   the existing wwnr_printk test to resolve flakiness.
   Additionally, fixed an issue in the selftests framework where negative
   assertion failures were not correctly propagated due to shell rules.
 
 - Fix 32-bit build of nomiss KUnit test
 
   A previous commit introduced a division between an u64 and a constant
   value and that doesn't build on 32-bit systems. Use div_u64() instead.
 
 - Document changes in sleep monitor
 
   The sleep monitor introduced some changes in the past like allowing
   epoll_wait() as a valid sleep and a task going to runnable before
   scheduling as a valid wakeup. Document both.
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Merge tag 'trace-rv-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull Real-time Verifier updates from Steven Rostedt:

 - Switch LTL and DOT parsers to Lark in code generation tool

   The rvgen code generation tool originally parsed DOT files and LTL
   specifications using custom string parsing and Ply, which is no
   longer maintained. The DOT parser was fragile and prone to failure on
   minor format variations. Both LTL and DOT parsers have been rewritten
   to use the Lark parsing library.

 - Simplify Hybrid Automata clock variables

   The clock variables in hybrid automata monitors now use a single
   representation of the elapsed time since the clock was reset, rather
   than converting between invariant and guard representations. This
   allows simpler code generation for the newly refactored parser.

 - Generate cleanup hook for per-obj monitor

   The code generation scripts now adds a cleanup function to per-obj
   monitors for the user to wire to the appropriate event (e.g.
   sched_process_exit for tasks).

 - Reduce read_lock scope during per-task cleanup

   Take the tasklist_lock only when necessary, that is when iterating
   over for_each_process_thread().

 - Simplify task monitor slot management

   Only rely on the slot array for per-task slot management to avoid
   inconsistency with the unused counter.

 - Improve rvgen code robustness and templates

   Use pathlib in rvgen and improve kernel path discovery. Also improve
   consistency across templates when generating code (e.g. author
   placeholder and monitor struct name).

 - Update rtapp sleep monitor

   Simplify the sleep monitor by excluding kernel threads and updating
   the nanosleep check to focus only on CLOCK_REALTIME. Also switch to
   use the sched_exit tracepoint to run in the context of the offending
   (wakee) task.

 - Add wakeup monitor

   Add the new rtapp/wakeup monitor to detect when lower-priority tasks
   wake up higher-priority ones, complementing the existing sleep
   monitor by running in the waker context and capturing its stack
   trace.

 - Fix tools/rv exit status on failure

   Ensure the rv tool returns a failure exit code when a monitor fails
   to start because it was already running.

 - Add automated selftests for tools/rv and rvgen

   Introduced automated bash selftests to validate rv monitor listing
   and execution under different configurations. Added tests for the
   rvgen code generator, validating generated files against expected
   output (golden). Tests are reachable via make check.

 - Add KUnit test coverage for verification monitors

   Added comprehensive KUnit tests to validate the functionality of
   deterministic, hybrid, and LTL monitors by emulating event sequences
   and timing in a mock environment without affecting the running kernel
   while expecting mock reactions to fire. Ensure real RV monitors
   cannot run during KUnit tests to avoid state corruption.

 - Mock current in rv monitors

   Mock the call to current in rv monitors when the KUnit tests are
   built to allow them to run the test on dummy tasks. No overhead is
   expected when KUnit tests aren't running.

 - Introduce rvgen kunit subcommand

   Added a new 'kunit' subcommand to rvgen to automatically patch an
   already generated monitor with KUnit integration templates by parsing
   its event handlers and creating the required mock structures and
   initializations.

 - Refine kernel verification selftests

   Added new selftests for the deadline and stall monitors and
   rearranged the existing wwnr_printk test to resolve flakiness.
   Additionally, fixed an issue in the selftests framework where
   negative assertion failures were not correctly propagated due to
   shell rules.

 - Fix 32-bit build of nomiss KUnit test

   A previous commit introduced a division between an u64 and a constant
   value and that doesn't build on 32-bit systems. Use div_u64()
   instead.

 - Document changes in sleep monitor

   The sleep monitor introduced some changes in the past like allowing
   epoll_wait() as a valid sleep and a task going to runnable before
   scheduling as a valid wakeup. Document both.

* tag 'trace-rv-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (40 commits)
  Documentation/rv: Explain epoll and aborted sleeps
  rv: Fix 32-bit build of nomiss KUnit test
  selftests/verification: Add selftests for deadline and stall monitors
  selftests/verification: Rearrange the wwnr_printk test
  selftests/verification: Fix wrong errexit assumption
  rv: Add KUnit tests for some LTL monitors
  rv: Add KUnit mock for current
  rv: Add KUnit tests for some DA/HA monitors
  rv: Export task monitor slot and react symbols
  verification/rvgen: Add selftests for rvgen kunit
  verification/rvgen: Add the rvgen kunit subcommand
  verification/rvgen: Add selftests
  verification/rvgen: Add golden and spec folders for tests
  tools/rv: Add selftests
  verification/rvgen: Improve consistency in template files
  verification/rvgen: Use pathlib instead of os.path
  verification/rvgen: Improve rv_dir discovery in RVGenerator
  tools/rv: Fix exit status when monitor execution fails
  rv: Use generic rv_this for the rv_monitor variable in LTL
  rv/rtapp: Add wakeup monitor
  ...
2026-08-19 13:29:22 -07:00
Vincent Donnefort
8b502bf6eb ring-buffer: Remove ring_buffer_per_cpu::mapped
ring_buffer_per_cpu::mapped tracks if a ring-buffer is either mapped by
user-space or if it is a persistent buffer. We already have user_mapped
for the former and ring_meta for the latter. Get rid of mapped and
instead create rb_is_static(). A static ring-buffer cannot be resized,
swapped or have its pages extracted.

Link: https://patch.msgid.link/20260813131152.3589632-10-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:26:18 -04:00
Vincent Donnefort
d9b5e22bf2 ring-buffer: Remove trace_buffer::cpus
The 'cpus' field in struct trace_buffer became useless in commit
8e7b58c27b ("ring-buffer: Just update the subbuffers when changing their
allocation order"). Remove it

Link: https://patch.msgid.link/20260813131152.3589632-9-vdonnefort@google.com
Fixes: 8e7b58c27b ("ring-buffer: Just update the subbuffers when changing their allocation order")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:26:13 -04:00
Vincent Donnefort
472ac478b1 ring-buffer: Dynamically calculate max_data_size
The ring buffer order can be dynamically modified and temporarily
disables writing to do so. It is therefore safe to use the updated value
to calculate the maximum event size which can be written onto the ring
buffer.

However, notice it is hardly making any difference for trace_marker
because of the TRACE_MARKER_MAX_SIZE limit. For an 8KiB subbuf size,
trace_marker can take 4096 characters while it can 'only' take 4054
bytes for smaller subbufs.

Link: https://patch.msgid.link/20260813131152.3589632-8-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:26:07 -04:00
Vincent Donnefort
e743527c5b ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()
ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set,
it can allocate a reader page with an outdated order. This isn't a big
issue, the user can still re-allocate a new reader page and try again.

However, what is more problematic is if the value of subbuf_order
changes in the middle of ring_buffer_alloc_read_page(). In that case,
bpage->order might not match the actual allocated memory.

Use bpage->order for the allocation to prevent this race.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813131152.3589632-6-vdonnefort@google.com
Fixes: bce761d757 ("ring-buffer: Read and write to ring buffers with custom sub buffer size")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:19:12 -04:00
Vincent Donnefort
8a5f636378 ring-buffer: Fix subbuf resize race with ring buffer readers
trace_buffer subbuf_size is read lockless in ring_buffer_read_page() and
ring_buffer_read_start(), while it can simultaneously be resized with
ring_buffer_subbuf_order_set().

Instead of trace_buffer::subbuf_size, use bpage::order in
ring_buffer_read_start() and ring_buffer_read_page().

In ring_buffer_read_start(), even with resize_disabled, there is still a
possibility of a race with a buffer modification. Hold the trace_buffer
mutex to synchronise with any pending ring buffer order modification.

trace_buffer::subbuf_size is now actually useless, remove it. Also,
create accessors rb_subbuf_capacity() and rb_page_capacity() which
return the actual size available for storing events, while
rb_subbuf_size() returns the actual subbuf page-size.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813131152.3589632-5-vdonnefort@google.com
Fixes: f9b94daa54 ("ring-buffer: Set new size of the ring buffer sub page")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260805153225.2096152-1-vdonnefort%40google.com # patch 1
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:19:04 -04:00
Vincent Donnefort
7a1fb95de5 ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
Discarding a cached reader page after a concurrent ring buffer resize
uses the new global subbuf_order for the free_pages() call. This
mismatched order may crashes the kernel or leaks memory because the cached
page was allocated under the old size.

Save the actual free_page order alongside the page address to ensure we
always refer to the correct value and do not rely on the potentially
stalled cpu_buffer->subbuf_order value. The simplest is to make
free_page a buffer_data_read_page which already covers exactly what we
need: a page address and a page order.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813131152.3589632-4-vdonnefort@google.com
Fixes: 8e7b58c27b ("ring-buffer: Just update the subbuffers when changing their allocation order")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:14:21 -04:00
Vincent Donnefort
24974bd0da ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
Because, ring_buffer_subbuf_order_set() can clear cpu_buffer->free_page,
hold cpu_buffer->lock to prevent races with
ring_buffer_alloc_read_page() and ring_buffer_free_read_page().

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813131152.3589632-3-vdonnefort@google.com
Fixes: 8e7b58c27b ("ring-buffer: Just update the subbuffers when changing their allocation order")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260810125633.3344684-1-vdonnefort%40google.com # patch 3
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:13:38 -04:00
Vincent Donnefort
234b1a72e9 ring-buffer: Free cpu_buffer::free_page with subbuf_order
When sub-buffers use an order greater than 0, cpu_buffer->free_page is
allocated with subbuf_order. Use the correct order for
cpu_buffer->free_page.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813131152.3589632-2-vdonnefort@google.com
Fixes: f9b94daa54 ("ring-buffer: Set new size of the ring buffer sub page")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260806211306.3704194-1-vdonnefort%40google.com # patch 3
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 13:12:16 -04:00
Steven Rostedt
ae70b04ab9 tracing: Have trace_event_update_all() only handle module that is loading
The function trace_event_update_all() does a scan of events looking to
replace enums with their values in the strings that get exported to the
event format files. It's run at boot up on all events and again when a
module loads.

The issue is that when a module loads, it still runs on *all* events.
There's no reason to process every event when a module loads as the
previous events have already been processed. Only execute on the events
that are loaded with the module.

Link: https://patch.msgid.link/20260813204226.29563591@gandalf.local.home
Fixes: 3673b8e4ce ("tracing: Allow for modules to convert their enums to values")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-14 09:59:27 -04:00
Michael Wu
c3730b8373 tracing: Fix race between update_event_fields and, event_define_fields
The following sequence may leads race between event_define_fields()
and update_event_fields():

 CPU0 (loads module A)                      CPU1 (loads module B)
 ===============================            ===============================
 load_module(A)                             load_module(B)
   notifier_call_chain                        notifier_call_chain
     trace_module_notify                        trace_module_notify
       mutex_lock(&event_mutex)                   trace_event_update_all()
         trace_module_add_events(A)                 down_write(&trace_event_sem)
            __register_event(call_A)
              __add_event_to_tracers(call_A)
                event_define_fields(call_A)
                  for each f:                         list_for_each_entry(field,
                    list_add(&f->link,                                    &class->fields, link)
                             &class->fields)            field = class->fields->next;

Where access to the class->fields is not protected by the event_mutex in
trace_event_update_all().

This produces the following panic:
   Unable to handle kernel access ... at virtual address 0000000000000018
   pc : update_event_fields+0xf8/0x368
   Call trace:
    update_event_fields+0xf8/0x368
    trace_event_update_all+0x7c/0x2b4
    trace_module_notify+0x4c/0x1dc
    notifier_call_chain+0x84/0x168
    blocking_notifier_call_chain_robust+0x64/0xd4
    load_module+0x10c8/0x123c
    __arm64_sys_finit_module+0x230/0x31c

Fix by taking event_mutex in trace_event_update_all() before
trace_event_sem.

Cc: stable@vger.kernel.org
Fixes: b3bc8547d3 ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well")
Link: https://patch.msgid.link/2e5730d2-c631-da41-3a3a-ae35bb4895f3@allwinnertech.com
Signed-off-by: Michael Wu <michael@allwinnertech.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-13 15:38:25 -04:00
Hui Su
b69859204d tracing: Fix NULL pointer dereference in module event cache removal
A module-only event filter such as ":mod:foo" is cached with a NULL
event_mod->match when foo has not been loaded. If a later write tries to
remove a specific match from the same module, remove_cache_mod() passes
the NULL cached match to strcmp(), causing a NULL pointer dereference.

The issue can be reproduced from userspace:

  echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event
  echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event

The second write must be a concatenation (">>") to not include O_TRUNC as
that would cause ftrace_clear_events() to clear the cached modules lines.

The crash was reproduced on x86_64 QEMU while KUnit workers contended on
the event tracing path:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  RIP: 0010:strcmp+0x10/0x30
  Call Trace:
   __ftrace_set_clr_event_nolock+0x373/0x4a0
   ftrace_set_clr_event+0xf0/0x180
   ftrace_event_write+0xdf/0x110
   vfs_write+0xf6/0x440
   ksys_write+0x68/0xe0
   do_syscall_64+0xf9/0x540
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

Check event_mod->match before comparing it, consistent with the existing
NULL checks for the cached system and event fields. The mismatched removal
continues to return -EINVAL; a broad cached module filter is removed with
"!:mod:<module>".

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260811173902.1927376-2-sh_def@163.com
Fixes: b355247df1 ("tracing: Cache \":mod:\" events for modules not loaded yet")
Reported-by: syzbot+4d3143c8e28f6266c636@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/6a7a6b7f.9c11d2ce.289b96.00f8.GAE@google.com/
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-13 15:38:03 -04:00
Hui Zhu
7c6beeb8c8
bpf: Make bpf_trampoline_multi_detach return void
bpf_trampoline_multi_detach() always returns 0 and the sole caller
ignores the return value.  Change it to return void and drop the
WARN_ON_ONCE at the call site.

Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/12beba657f5c9e86a016a097750209287a2f262a.1786412280.git.zhuhui@kylinos.cn
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-08-13 02:52:23 +02:00
Julia Lawall
b16b03ebb3 ring-buffer: drop unneeded semicolon
When a function-like macro expands to an expression, that expression
doesn't need a semicolon after it.  All uses have been verified to
have their own semicolons.

This was found using the following Coccinelle semantic patch:

@r@
identifier i : script:ocaml() { String.lowercase_ascii i = i };
expression e;
@@

*#define i(...) e;

Link: https://patch.msgid.link/20260801191002.1383835-6-Julia.Lawall@inria.fr
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-11 15:38:43 -04:00
Steven Rostedt
a8aaf7445b tracing: Cleanup event_enable_trigger_parse() by using __free()
The enable_data variable gets freed on most error paths in
event_enable_trigger_parse(). Use free() to free it and just before
returning normally, call retain_and_null_ptr(enable_data) just before a
successful exit to keep it from being freed. On success, the enable_data
is assigned to the trigger_data->private_data field.

Also add a comment to why event_trigger_free(trigger_data) is being called
before a successful exit.

Link: https://patch.msgid.link/20260807113558.0ff14e96@gandalf.local.home
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-11 10:23:38 -04:00
David Carlier
0456323ddd tracing: Report every TP_printk double dereference
WARN_ONCE() splats once per call site, so only the first offending event
registered is ever reported. The tree currently has six:
ice_{rx,tx}_dim_template, two hfi1 txq events, mtu3_ep and edma_log_io.
Whichever registers first hides the rest, and each has to be found again
on the next boot.

Add a pr_warn() next to the WARN_ONCE() so every offender is listed, the
same way test_event_printk() already pairs WARN_ON_ONCE() with pr_warn()
for unsafe %p* dereferences. The WARN_ONCE() stays so the condition still
fails tests and panics under panic_on_warn.

Link: https://patch.msgid.link/20260806215256.1680267-1-devnexen@gmail.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-11 10:20:19 -04:00
Andrey Grodzovsky
b0c8570491 ftrace: deprecate disabling via ftrace_enabled sysctl
Writing 0 to kernel.ftrace_enabled has not reliably disabled ftrace
for years (FTRACE_OPS_FL_PERMANENT users already block it, and more
callers rely on ftrace always being on). Refuse the write instead of
leaving it in an inconsistent "disables some, not all" state: return
-EOPNOTSUPP and log a message. Reads and enabling (writing 1) are
unaffected.

Update the docs to note the deprecation up front.

Link: https://patch.msgid.link/20260806153000.4184871-2-andrey.grodzovsky@crowdstrike.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-10 21:21:18 -04:00
Masami Hiramatsu (Google)
29a86c5e63 fprobe: Simplify fprobe_remove_ips() by reusing existing helpers
fprobe_remove_ips() manually duplicates the unregister and filter-removal
logic for both graph and ftrace ops. Simplify it by delegating to the
existing fprobe_graph_remove_ips() and fprobe_ftrace_remove_ips() helpers.

Link: https://lore.kernel.org/all/178528139798.102586.5349128066643420018.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-10 17:13:20 +09:00
Hui Su
91542863ab ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
In test_ringbuffer()'s out_free cleanup loop, the check
`!rb_threads[cpu]` only catches NULL entries and misses entries that
hold an ERR_PTR.

rb_threads[] is static, so unassigned slots are NULL. But when
kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or
-EINTR) in rb_threads[cpu] before the creation loop jumps to out_free.
That entry is non-NULL, so the old `!ptr` check does not break, and the
cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop()
then dereferences the bogus pointer, crashing the kernel during the
late_initcall self-test.

crash logs:
  BUG: kernel NULL pointer dereference, address: 000000000000001c
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy)
  RIP: 0010:kthread_stop+0x2e/0x220
  RBX: fffffffffffffff4
  CR2: 000000000000001c
  Call Trace:
   <TASK>
   test_ringbuffer+0x1ec/0x650
   do_one_initcall+0x6c/0x2c0
   kernel_init_freeable+0x21d/0x420
   kernel_init+0x15/0x1c0
   ret_from_fork+0x21b/0x320
   </TASK>
  Kernel panic - not syncing: Fatal exception

Cc: stable@vger.kernel.org
Fixes: 64ed3a049e ("ring-buffer: make use of the helper function kthread_run_on_cpu()")
Link: https://patch.msgid.link/20260807154145.2846521-2-sh_def@163.com
Signed-off-by: Hui Su <sh_def@163.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:26:30 -04:00
Vincent Donnefort
6d014e44b6 ring-buffer: Initialise reader page order in rb_allocate_cpu_buffer()
In rb_allocate_cpu_buffer(), bpage->order was omitted, leaving it as 0.
This is an issue for a ring-buffer with subbufs bigger than PAGE_SIZE if
when freed: free_buffer_page() relies on this value. Align the value
with the actual allocation size (buffer::subbuf_order).

Cc: stable@vger.kernel.org
Fixes: f9b94daa54 ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/20260806211306.3704194-4-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:26:11 -04:00
Vincent Donnefort
bf98d7b0d5 ring-buffer: Prevent subbuf order change when resizing is disabled
Because ring_buffer_subbuf_order_set() frees buffer pages, we can't
allow it when resizing is disabled. A non-consuming reader is at risk of
use-after-free (rb_advance_iter()).

Return -EBUSY on resize_disabled, matching ring_buffer_resize()
behaviour.

Cc: stable@vger.kernel.org
Fixes: f9b94daa54 ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/20260806211306.3704194-3-vdonnefort@google.com
Reported-by: syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:23:45 -04:00
Vincent Donnefort
7c727dfce6 ring-buffer: Prevent resizing of persistent ring buffer
Dynamically resizing a persistent ring buffer is not possible. Disable
the feature.

Cc: stable@vger.kernel.org
Fixes: be68d63a13 ("ring-buffer: Add ring_buffer_alloc_range()")
Link: https://patch.msgid.link/20260806211306.3704194-2-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:23:18 -04:00
Josh Poimboeuf
8b8292d648 ftrace: Fix off-by-one fentry site disable in ftrace_free_mem()
When a module's init text is freed, do_init_module() calls
ftrace_free_mem() with a half-open [start, end) range.  However the
ftrace_cmp_recs() comparator treats the upper bound as inclusive, as all
its other users do, passing 'ip + size - 1'.  So ftrace_free_mem() can
delete a record sitting exactly at 'end', which is outside the freed
range.

For a kernel without CFI or IBT, the first record of a function is at
the function start, which for the first function in a module is also the
base of its text allocation.  As the module allocator packs its regions,
that address is often the 'end' passed by a neighboring module's
do_init_module(), causing the first function's ftrace location to get
disabled, preventing an attempt to livepatch it:

  livepatch: failed to find location for function 'pcspkr_probe'

Convert the exclusive end to the inclusive 'end - 1' the comparator
expects, and return early for an empty range to avoid the subtraction
from underflowing when the init text size is zero.

Cc: stable@vger.kernel.org
Fixes: 42c269c88d ("ftrace: Allow for function tracing to record init functions on boot up")
Link: https://patch.msgid.link/1b5ccfa8095bdb1277f84af1c2c2e2205aca03ae.1785992188.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:22:41 -04:00
Tengda Wu
f27bdc4307 ring-buffer: Use current_context for safe per-CPU buffer swap
The ring_buffer_swap_cpu() function currently checks the per-CPU
committing counter to determine if a buffer is actively being written to
before performing the swap. However, there exists a race window where
this check can be bypassed:

    ring_buffer_lock_reserve
        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a
        rb_reserve_next_event
            rb_start_commit // inc committing
            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
            __rb_reserve_next
                rb_move_tail
                    rb_end_commit(cpu_buffer);   // dec committing => 0
                    /* interrupt hits here, successfully swaps! */
                    local_inc(&cpu_buffer->committing);

    ring_buffer_unlock_commit
        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b
        rb_commit
            rb_end_commit
            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
                                                // triggers warning

The committing counter can temporarily drop to 0 during a single write
operation (within rb_move_tail), creating a window where swap can
succeed even though the write is still in progress. This leads to
inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().

Replace the committing counter check with current_context checks, which
are set at the entry of ring_buffer_lock_reserve() and remain valid
throughout the entire write operation, providing a reliable indicator of
buffer busy state during swap.

Cc: stable@vger.kernel.org
Fixes: 4239c38fe0 ("ring-buffer: Process commits whenever moving to a new page.")
Link: https://patch.msgid.link/20260803005640.2445666-2-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:22:06 -04:00
Anubhav Shelat
3cf6ee903c eventfs: Define event fields before directory creation
Move the event_define_fields() call in event_create_dir() before the
eventfs directory creation. Previously, a failure after directory
creation wouldn't clean up eventfs_inode because the error path didn't
call eventfs_remove_dir(). This eliminates the need to clean up the
eventfs directories if event_define_fields() fails.

Link: https://patch.msgid.link/20260715135231.338535-3-ashelat@redhat.com
Signed-off-by: Anubhav Shelat <ashelat@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 12:42:09 -04:00
Leon Hwang
48f2fd0d93 ftrace: Drop extra comma in trace_buffered_event_enable
Drop the extra comma in "scoped_guard()" to cleanup the code.

Link: https://patch.msgid.link/20260730150411.88667-5-leon.hwang@linux.dev
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:32 -04:00
Leon Hwang
092f8ec7db ftrace: Protect direct_functions in update_ftrace_direct_mod
Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-4-leon.hwang@linux.dev
Fixes: e93672f770 ("ftrace: Add update_ftrace_direct_mod function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:27 -04:00
Leon Hwang
f26e5fa75f ftrace: Protect direct_functions in update_ftrace_direct_del
Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-3-leon.hwang@linux.dev
Fixes: 8d2c1233f3 ("ftrace: Add update_ftrace_direct_del function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:23 -04:00
Leon Hwang
63444b7617 ftrace: Protect direct_functions in ftrace_find_rec_direct
Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-2-leon.hwang@linux.dev
Fixes: d05cb47066 ("ftrace: Fix modification of direct_function hash while in use")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:04 -04:00
Masami Hiramatsu (Google)
d093d4524b tracing/boot: Add support for eprobe, fprobe, and tprobe events
Boot-time tracing currently supports kprobe-events and synthetic-events
under per-event configuration options.

Extend boot-time tracing to support newly added dynamic probe types:
- event probes (eprobe) under the "eprobes" event group
- function probes (fprobe) under the "fprobes" event group
- tracepoint probes (tprobe) under the "tracepoints" or "tprobes"
  event group

To support this cleanly, update dyn_event_create() in trace_dynevent.c
so that passing NULL as the type parameter delegates to
create_dyn_event(), allowing generic creation of any registered
dynamic event type from a raw command string.

Update Documentation/trace/boottime-trace.rst accordingly to describe
the new per-event bootconfig options.

Link: https://lore.kernel.org/all/178613905149.259829.18185480460810689421.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Changes in v3:
 - Check return values of strscpy() and snprintf() in trace_boot_add_probe_event()
   to prevent silent buffer truncation when constructing probe event strings.

Changes in v2:
 - Fix raw command detection logic for eprobes, fprobes, and tprobes
   by requiring ':' or isspace() after type prefix.
 - Consolidate duplicate loop logic into trace_boot_add_probe_event()
   helper function.
2026-08-08 21:20:55 +09:00
Masami Hiramatsu (Google)
faa0e9064a tracing/mmiotrace: Use trace_assign_type() in mmio_print_mark()
In mmio_print_mark(), a raw C cast (struct print_entry *)entry is used to
obtain the print_entry pointer.

Use the standard trace_assign_type() macro instead, matching the usage in
mmio_print_rw() and mmio_print_map().

Link: https://patch.msgid.link/178524301013.56416.9116249028160618790.stgit@devnote2
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-07 20:45:58 -04:00
Daniel Borkmann
e1d9b82db5 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 7.2-rc7
Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2026-08-07 23:04:17 +02:00
Mykyta Yatsenko
d5b201ed4f tracing: Make per-template BTF id lists file-local
DECLARE_EVENT_CLASS emitted __bpf_trace_btf_ids_<call> through
BTF_ID_LIST_GLOBAL, i.e. a global symbol named after the event class.
The class name is not unique across the kernel, so the symbol
multiply-defines whenever two translation units instantiate the same
class.

Switch to the file-local BTF_ID_LIST: the list is reached
only through the event_class_<call>.btf_ids pointer, initialised in the
same unit, so tracefs readers never reference the symbol by name and
resolve_btfids still fills the now-local .BTF_ids entries.

The handcrafted syscall classes are the one cross-unit consumer: give
them their own local BTF_ID_LIST rather than importing the generated
sys_{enter,exit} lists.

Link: https://patch.msgid.link/20260730-b4-fix_btf_tracefs-v2-1-6b66da8dc103@meta.com
Fixes: eadc0725ab ("tracing: Expose tracepoint BTF ids via tracefs")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/ff58b01c-3f5e-4d55-be82-609d2faaf12e@sirena.org.uk/
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-05 22:02:29 -04:00
Lorenzo Stoakes
4276358f11 mm: prefer vma_[start,end]_pgoff() to vma->vm_pgoff in kernel/
Be consistent in using vma_start_pgoff() and vma_end_pgoff(), which clearly
indicates which part of the VMA the page offset refers to and aids
greppability.

This is part of a broader series laying the ground to provide a virtual
page offset for MAP_PRIVATE-file backed anon folios.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-19-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> # for kernel/dma
Reviewed-by: Gregory Price <gourry@gourry.net>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-08-04 19:19:01 -07:00
Gabriele Monaco
785095112f rv: Fix 32-bit build of nomiss KUnit test
Commit 8da2a88383 ("rv: Add KUnit tests for some DA/HA monitors")
introduced a division of a 64-bit value by 1000 in the nomiss KUnit
test. This does not compile on 32-bit systems, as standard division of
64-bit values leads to an undefined reference to __udivdi3.

Fix the build on 32-bit systems by using div_u64().

Fixes: 8da2a88383 ("rv: Add KUnit tests for some DA/HA monitors")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202608020311.hYjqOG5k-lkp@intel.com
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260803150622.322806-1-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-08-04 16:11:27 +02:00
Amery Hung
c0e091f30f
bpf: Rename ARG_CONST_SIZE{,_OR_ZERO} to ARG_MEM_SIZE{,_OR_ZERO}
ARG_CONST_SIZE does not require a constant: check_mem_size_reg() accepts
any bounded scalar and verifies the memory access against its maximum
(reg_umax). Rename ARG_CONST_SIZE and ARG_CONST_SIZE_OR_ZERO to
ARG_MEM_SIZE and ARG_MEM_SIZE_OR_ZERO to reflect that. ARG_CONST_ALLOC_
SIZE_OR_ZERO, which does require a constant, is left unchanged.

Pure rename, no functional change.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/bpf/20260801074633.1595644-10-ameryhung@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-08-03 00:29:14 +02:00
Linus Torvalds
2aa6a5e889 tracing fixes for v7.2:
- Reset dropped_count in mmio_reset_data()
 
   When mmio_reset_data() is called, it does not reset the dropped_count
   so that subsequent runs will have incorrect reporting.
 
 - Add NULL check for mmio_trace_array in logging functions
 
   The functions __trace_mmiotrace_rw() and __trace_mmiotrace_map()
   may have the 'tr' variable passed to it as NULL. But they both
   dereference it without checking if it is NULL first.
 
 - Check return value of __register_event() in trace_module_add_events()
 
   If __register_event() fails, the call after it (__add_event_to_tracers())
   will create a file for it. If the module fails to load and its memory
   is freed, the file will still point to it and it will not be removed
   as the registering of the event did not complete. Only call
   __add_event_to_tracers() if the __register_event() was successful.
 
 - Fix false positive match in regex_match_full()
 
   The regex full matching uses a strncmp() to test against the match
   string and the value. It should not match if value is a prefix of
   the string to match. Check to make sure the length of the strings
   match before comparing.
 
 - Fix reader page read offset for remote buffers
 
   A page swapped in by __rb_get_reader_page_from_remote() retains its
   stale read offset, causing subsequent reads to skip events or read
   past valid data.
 
 - Fix memory leak of subbuf_ids in rb_allocate_cpu_buffer()
 
   Remote buffers allocate a subbuf_ids array. If the allocator function
   fails after it is allocated, it does not free it, resulting in a
   memory leak.
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Merge tag 'trace-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Reset dropped_count in mmio_reset_data()

   When mmio_reset_data() is called, it does not reset the dropped_count
   so that subsequent runs will have incorrect reporting.

 - Add NULL check for mmio_trace_array in logging functions

   The functions __trace_mmiotrace_rw() and __trace_mmiotrace_map() may
   have the 'tr' variable passed to it as NULL. But they both
   dereference it without checking if it is NULL first.

 - Check return value of __register_event() in trace_module_add_events()

   If __register_event() fails, the __add_event_to_tracers() call after
   it will create a file for it. If the module fails to load and its
   memory is freed, the file will still point to it and it will not be
   removed as the registering of the event did not complete.

   Only call __add_event_to_tracers() if the __register_event() was
   successful.

 - Fix false positive match in regex_match_full()

   The regex full matching uses a strncmp() to test against the match
   string and the value. It should not match if value is a prefix of the
   string to match. Check to make sure the length of the strings match
   before comparing.

 - Fix reader page read offset for remote buffers

   A page swapped in by __rb_get_reader_page_from_remote() retains its
   stale read offset, causing subsequent reads to skip events or read
   past valid data.

 - Fix memory leak of subbuf_ids in rb_allocate_cpu_buffer()

   Remote buffers allocate a subbuf_ids array. If the allocator function
   fails after it is allocated, it does not free it, resulting in a
   memory leak.

* tag 'trace-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Fix subbuf_ids memory leak in rb_allocate_cpu_buffer() error path
  ring-buffer: Fix reader page read offset for remote buffers
  tracing/filters: Fix false positive match in regex_match_full()
  tracing: Check return value of __register_event() in trace_module_add_events()
  tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions
  tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
2026-07-31 20:24:11 -07:00
Masami Hiramatsu (Google)
260b20d9b7 ring-buffer: Fix subbuf_ids memory leak in rb_allocate_cpu_buffer() error path
In rb_allocate_cpu_buffer(), cpu_buffer->subbuf_ids is allocated using
kcalloc() when buffer->remote is non-NULL. If a subsequent page allocation
fails (e.g., ring_buffer_desc_page() returns NULL or rb_allocate_pages()
fails), execution jumps to fail_free_reader.

While __free(kfree) automatically frees the outer cpu_buffer structure
at scope exit, kfree(cpu_buffer) does not recursively free nested heap
pointers such as cpu_buffer->subbuf_ids, resulting in a memory leak.

Fix this by explicitly freeing cpu_buffer->subbuf_ids in the
fail_free_reader error unwinding path when cpu_buffer->remote is set.

Link: https://patch.msgid.link/178550740672.380917.6067449683620196150.stgit@devnote2
Fixes: 2e67fabd8b ("ring-buffer: Introduce ring-buffer remotes")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-31 19:48:27 -04:00
Gabriele Monaco
51f3fe704a rv: Add KUnit tests for some LTL monitors
Validate the functionality of LTL monitors by injecting events in a
controlled environment (KUnit) and expecting reactions, just like it is
done in DA monitors.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260723074534.43521-15-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31 16:27:46 +02:00
Gabriele Monaco
cf8f191c06 rv: Add KUnit mock for current
Some monitors do not only rely on tracepoint arguments but also on the
currently executing task.
This makes it more challenging to mock events in KUnit.

Define wrapper functions around current, the functionality is mocked
only during KUnit, an additional function call is avoided using a static
branch unless any (even unrelated) KUnit test is running.

Rely on a global mock_current variable that is set only by the RV KUnit
tests and cleared on teardown. Unrelated KUnit tests that happen to
trigger RV handlers would see it null and use current.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Link: https://lore.kernel.org/r/20260723074534.43521-14-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31 16:27:45 +02:00
Gabriele Monaco
8da2a88383 rv: Add KUnit tests for some DA/HA monitors
Validate the functionality of DA monitors by injecting events in a
controlled environment (KUnit) and expecting reactions.

Events handlers are exported directly from the monitor source files
without using system events and with dummy arguments (e.g. no real
tasks). If the provided sequence of events incurs a violation, the test
expects the stub version of rv_react() to be called.

This testing method can validate the entire monitor implementation since
it sits between the monitor and the system (in place of the
tracepoints). All sorts of system and timing events can be emulated
without affecting the running kernel.

Handlers and monitor functions are exported as part of a struct to
simplify the process of running KUnit tests from kernel modules.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260723074534.43521-13-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31 16:27:45 +02:00
Gabriele Monaco
be22e55b37 rv: Export task monitor slot and react symbols
Export rv_get_task_monitor_slot, rv_put_task_monitor_slot, and rv_react
to GPL modules so they can be accessed by KUnit and future monitors
built as kernel modules.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260723074534.43521-12-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31 16:27:45 +02:00
Gabriele Monaco
d9e4c61a12 rv: Use generic rv_this for the rv_monitor variable in LTL
Align the rv_monitor variable name in LTL to the generic rv_this as it
is already done for DA/HA monitors. This improves consistency and eases
assumptions across model classes.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260723074534.43521-2-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-31 13:53:51 +02:00
Vincent Donnefort
78cd56c2a9 ring-buffer: Fix reader page read offset for remote buffers
A page swapped in by __rb_get_reader_page_from_remote() retains its
stale read offset, causing subsequent reads to skip events or read
past valid data. Fix it.

Link: https://patch.msgid.link/20260729133609.4022734-1-vdonnefort@google.com
Fixes: fbd1743ecb ("ring-buffer: Add non-consuming read for ring-buffer remotes")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Reviewed-by: Keir Fraser <keirf@google.com>
Tested-by: Keir Fraser <keirf@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 19:41:14 -04:00
Masami Hiramatsu (Google)
c22c7b735f tracing/filters: Fix false positive match in regex_match_full()
regex_match_full() calls strncmp(str, r->pattern, len) where len is the
target field buffer size. When len is smaller than r->len (the filter
pattern length), strncmp() checks only len bytes of r->pattern against
str. If those len bytes match, strncmp() returns 0, resulting in a
false-positive match where a shorter string in a fixed-size field
matches a longer filter pattern.

For example, a 4-byte static string field containing "abcd" matched the
filter pattern "abcdefgh" because strncmp("abcd", "abcdefgh", 4)
returned 0. In this case, @len does NOT include '\0' because it is
fixed-size array.

Fix this by returning 0 (no match) early when len < r->len.

Fixes: 1889d20922 ("tracing/filters: Provide basic regex support")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178528488779.124250.5571741156199253769.stgit@devnote2
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:32:11 -04:00
Masami Hiramatsu (Google)
ac8719969e tracing: Check return value of __register_event() in trace_module_add_events()
trace_module_add_events() ignores the return value of __register_event()
and unconditionally calls __add_event_to_tracers() for each event.

If __register_event() fails (for example, if event_init() fails), the
trace_event_call is not added to ftrace_events list, but
__add_event_to_tracers() still creates a trace_event_file pointing to it.
If module loading subsequently fails and module memory is freed, tracing
state retains a stale trace_event_call pointer in trace_event_file,
leading to a use-after-free when tracefs or tracing subsystem operations
are later executed.

Fix this by checking the return value of __register_event() and only
calling __add_event_to_tracers() if event registration succeeded.

Fixes: ae63b31e4d ("tracing: Separate out trace events from global variables")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178528487878.124250.14170824576025743236.stgit@devnote2
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:32:11 -04:00
Masami Hiramatsu (Google)
12b80cdbc5 tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions
mmio_trace_rw() and mmio_trace_mapping() retrieve mmio_trace_array into
tr and pass it to __trace_mmiotrace_rw() and __trace_mmiotrace_map().
If these functions are invoked while mmio_trace_array is NULL (e.g. before
initialization or after disabled), accessing tr->array_buffer.buffer will
result in a NULL pointer dereference crash.

Fix this by adding an explicit NULL check for tr at the beginning of
__trace_mmiotrace_rw() and __trace_mmiotrace_map().

Link: https://patch.msgid.link/178524300062.56416.8362487250709962380.stgit@devnote2
Fixes: f984b51e07 ("ftrace: add mmiotrace plugin")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:27:55 -04:00
Masami Hiramatsu (Google)
c786d2bdf1 tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
mmio_reset_data() is called during tracer initialization, reset, and
start. While it resets overrun_detected and prev_overruns, it neglects
to reset dropped_count. Consequently, dropped event counts from prior
tracing sessions persist in dropped_count and corrupt overrun reports
in subsequent runs.

Fix this by explicitly calling atomic_set(&dropped_count, 0) in
mmio_reset_data().

Link: https://patch.msgid.link/178524299122.56416.16277704230639425172.stgit@devnote2
Fixes: 173ed24ee2 ("mmiotrace: count events lost due to not recording")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-29 14:27:55 -04:00
Masami Hiramatsu (Google)
8cf2f40ceb fprobe: Fix module reference count leak on error in register_fprobe()
In register_fprobe(), get_ips_from_filter() resolves target function
addresses and increments module reference counts via try_module_get() for
symbols in kernel modules. If get_ips_from_filter() fails on the second
pass and returns an error, register_fprobe() returned directly without
releasing module references acquired up to that point.

Fix this by ensuring the cleanup loop executing module_put() runs even when
get_ips_from_filter() returns a negative error.

Link: https://lore.kernel.org/all/178528125360.101985.4144133640239273153.stgit@devnote2/

Fixes: d24fa977ee ("tracing: fprobe: Fix to lock module while registering fprobe")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-29 22:50:02 +09:00
Raushan Patel
aca0cd1bf1 tracing/fprobe: Roll back on enable_trace_fprobe() failure
enable_trace_fprobe() sets the file link or the TP_FLAG_PROFILE flag and
then registers each trace_fprobe in the probe list. If
__register_trace_fprobe() fails partway through, the function returns
immediately without unregistering the trace_fprobes it already registered
or undoing the file link / flag it set, leaving the event half-enabled and
leaking the registered fprobe(s).

enable_trace_kprobe() already handles this with a rollback path. Do the
same for fprobe: on failure, unregister all probes and clear the file link
or profile flag.

Link: https://lore.kernel.org/all/20260724064208.480030-1-raushan.jhon@gmail.com/

Fixes: 334e5519c3 ("tracing/probes: Add fprobe events for tracing function entry and exit.")
Cc: stable@vger.kernel.org
Signed-off-by: Raushan Patel <raushan.jhon@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-29 00:27:52 +09:00
Raushan Patel
00a8ce2a2a tracing/probes: Reject $arg0 in meta argument expansion
traceprobe_expand_meta_args() parses $argN with simple_strtoul() and
calls sprint_nth_btf_arg(n - 1, ...). For $arg0, n is 0 so the index is
-1. Because ctx->nr_params is signed, the "idx >= nr_params" guard in
sprint_nth_btf_arg() does not catch the negative index, and
ctx->params[-1].name_off is read out of bounds.

The normal per-argument path (parse_probe_vars()) already rejects
$arg0 via its argument-number check, but meta-argument expansion runs
before per-argument parsing and substitutes the value first, bypassing
that check.

Reject $arg0 explicitly during expansion.

Link: https://lore.kernel.org/all/20260724054435.146279-1-raushan.jhon@gmail.com/

Fixes: 18b1e870a4 ("tracing/probes: Add $arg* meta argument for all function args")
Cc: stable@vger.kernel.org
Signed-off-by: Raushan Patel <raushan.jhon@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-28 23:58:31 +09:00
Masami Hiramatsu (Google)
c00e735410 tracing/probes: Treating longer symbol name on event comparation
MAX_COMMON_HEAD_LEN (63) was used to allocate a temporary buffer for
formatting command heads in trace_kprobe_match_command_head() and
trace_uprobe_match_command_head(). However, the buffer size is too
short for some longer symbols. Especially, with rust code, the symbol
can be mangled and become very long.

Refactor trace_kprobe_match_command_head() to perform direct string
comparisons using strcmp() and strncmp(), eliminating the need for a
temporary buffer and removing the MAX_COMMON_HEAD_LEN string length
restriction on probe symbol names.

For trace_uprobe_match_command_head(), since tu->filename is already
matched via strncmp(), use a fixed 64-byte stack buffer solely for
formatting offset and ref_ctr_offset (which requires at most 39 bytes).

With all users converted, remove the MAX_COMMON_HEAD_LEN definition from
trace_probe.h.

Link: https://lore.kernel.org/all/178521361102.34226.9650586522488974115.stgit@devnote2/

Reported-by: Zhan Xusheng <zhanxusheng1024@gmail.com>
Link: https://lore.kernel.org/all/20260724023317.624074-1-zhanxusheng@xiaomi.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-28 23:55:35 +09:00
Woradorn Laodhanadhaworn
efdcfd9b4f tracing: Use seq_buf for string concatenation
In preparation for removing the strlcat API[1],
replace the string concatenation logic with a struct seq_buf,
which tracks the current position and the remaining space internally.

Use seq_buf_str() to NUL-terminate before passing to early_enable_events().

Link: https://github.com/KSPP/linux/issues/370 [1]

Link: https://patch.msgid.link/20260713045249.69942-1-woradorn.laon@gmail.com
Signed-off-by: Woradorn Laodhanadhaworn <woradorn.laon@gmail.com>
[ Moved placement of #include <linux/seq_buf.h> ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:50 -04:00
Po-Sheng Lin
dca6a22aee tracing: Use strscpy() instead of strcpy() in trace_sched_switch
Replace strcpy() with strscpy() in __trace_find_cmdline() for
consistency with the existing strscpy() call in the same function,
and to avoid potential buffer overflow as flagged by the Kernel
Self Protection Project.

Link: https://patch.msgid.link/20260705173648.5418-1-posheng.lin.tw@gmail.com
Signed-off-by: Po-Sheng Lin <posheng.lin.tw@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:50 -04:00
Steven Rostedt
b5cc230af5 tracing: Warn when an event dereferences a pointer in TP_printk()
Currently on boot up and when modules are loaded, the trace event
infrastructure will examine the TP_printk's of every event looking to see
if it dereferences pointers on the ring buffer via printk formats like
"%pB" and such. What it doesn't do is check if the arguments themselves
do a dereference from a pointer.

This was brought with a fix[1] to the fsl_edma event that had in the
arguments of the TP_printk(): "__entry->edma->membase"

The __entry->edma is a pointer saved in the ring buffer. The dereference
from TP_printk() happens when the user reads the "trace" file which can be
seconds, minutes, hours, days, weeks, or even months later! There is no
guarantee that the __entry->edma pointer will still be pointing to what it
was when it was recorded, and could crash the kernel when a user reads the
event.

Add logic to the test_event_printk() that also checks for this case and
warn if the event dereferences a pointer from the ring buffer.

[1] https://lore.kernel.org/all/20260630200022.1826420-1-martin@kaiser.cx/

Link: https://patch.msgid.link/20260630184836.74d477b6@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Martin Kaiser <martin@kaiser.cx>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:50 -04:00
Samuel Moelius
693dc27c52 tracing: Reject invalid preemptirq_delay_test CPU affinity
preemptirq_delay_test accepts cpu_affinity as a module parameter and,
when it is non-negative, writes that CPU directly into a temporary
cpumask from the worker thread.  Values outside nr_cpu_ids can set a bit
outside the allocated cpumask before the test reports a normal affinity
error.

Validate the requested CPU in preemptirq_delay_run() before setting it
in the temporary cpumask.  Invalid affinity requests are reported by
the test thread and skipped before cpumask_set_cpu() can touch an
out-of-range bit.

Link: https://patch.msgid.link/20260628131021.2208632.6a5c6c959813.preemptirq-delay-test-invalid-cpu-affinity@trailofbits.com
Assisted-by: Codex:gpt-5.5-cyber-preview
Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:50 -04:00
Markus Elfring
73301fb81a fgraph: Use trace_seq_putc() in print_graph_return()
A single closing curly bracket should be put into a trace sequence buffer.
Thus use the corresponding function “trace_seq_putc”.

The source code was transformed by using the Coccinelle software.

Link: https://patch.msgid.link/d215fa89-9a62-4067-86ec-833290f35c80@web.de
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:50 -04:00
Markus Elfring
0ac2611f10 tracing/user_events: Replace a seq_printf() call by seq_puts() in user_seq_show()
A single string should be put into a sequence within a loop.
Thus use the corresponding function “seq_puts” for one selected call.

The source code was transformed by using the Coccinelle software.

Link: https://patch.msgid.link/1cf327f0-49a6-477f-a06f-2b22a167db24@web.de
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:49 -04:00
Markus Elfring
6e6179ad94 tracing/user_events: Use seq_putc() in two functions
Single characters should be put into a sequence. Thus use the corresponding
function “seq_putc” for selected calls.

The source code was transformed by using the Coccinelle software.

Link: https://patch.msgid.link/6bcaa4da-05c6-4097-90f5-3969f8a1dfbc@web.de
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:49 -04:00
Pengpeng Hou
935601a427 tracing: Bound histogram expression strings with seq_buf
expr_str() allocates a fixed MAX_FILTER_STR_VAL buffer and then builds
expression names with a series of raw strcat() appends. Nested operands,
constants, field flags, and generated field names can push the rendered
string past that fixed limit before the name is attached to the hist
field.

Build expression strings with seq_buf and return -E2BIG when the
rendered name would exceed MAX_FILTER_STR_VAL. This keeps the existing
tracing-side limit while replacing the raw append logic with bounded
construction.

Link: https://patch.msgid.link/20260611055945.22348-4-pengpeng@iscas.ac.cn
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:49 -04:00
Pengpeng Hou
a5ca27e8ff tracing: Return ERR_PTR() from expr_str()
expr_str() currently reports all failure cases as NULL, so callers cannot
distinguish invalid recursion depth from allocation failure or later
string construction errors.

Return ERR_PTR()-encoded errors from expr_str() and make parse_unary()
and parse_expr() propagate them. Clear expr->name before destroying the
hist field so the error pointer is not freed as a string.

Link: https://patch.msgid.link/20260611055945.22348-3-pengpeng@iscas.ac.cn
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:49 -04:00
Pengpeng Hou
988995c055 tracing: Use __free() for expr_str() buffer
expr_str() allocates a temporary expression buffer and manually frees it
on some error paths.

Convert the buffer to __free(kfree) and return it with return_ptr() on
success. This keeps ownership handling separate from the later ERR_PTR()
conversion and string-bound change.

Link: https://patch.msgid.link/20260611055945.22348-2-pengpeng@iscas.ac.cn
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:49 -04:00
David Laight
b11d9af16d kernel/trace/trace_printk: Use kstrdup() instead of kmalloc() and strcpy()
Link: https://patch.msgid.link/20260606202633.5018-34-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:48 -04:00
Yu Peng
8432a8772b tracing: Point constant hist field type to string literal
The HIST_FIELD_FL_CONST path uses the fixed "u64" type string.

Point hist_field->type directly to the string literal, matching the
HIST_FIELD_FL_HITCOUNT path. The release path already uses kfree_const(),
so no duplication is needed.

Link: https://patch.msgid.link/20260527023450.2137639-1-pengyu@kylinos.cn
Signed-off-by: Yu Peng <pengyu@kylinos.cn>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:48 -04:00
Mykyta Yatsenko
eadc0725ab tracing: Expose tracepoint BTF ids via tracefs
Add events/<sys>/<event>/btf_ids, a per-template file that exposes
the BTF ids resolve_btfids fills in for each tracepoint:

  btf_obj_id  BTF object owning the ids below
  raw_btf_id  FUNC_PROTO of __bpf_trace_<call> (named args), consumed
              by raw_tp / tp_btf BPF programs
  tp_btf_id   trace_event_raw_<call> ring-buffer record, consumed by
              classic BPF_PROG_TYPE_TRACEPOINT programs

DECLARE_EVENT_CLASS now emits a 2-entry BTF_ID_LIST (FUNC __bpf_trace_*
and STRUCT trace_event_raw_*) and stores the pointer in
trace_event_class.

Per-syscall events under syscalls/ share the handcrafted classes
event_class_syscall_{enter,exit} instead of going through
DECLARE_EVENT_CLASS. Wire those classes to the BTF id lists
generated for sys_enter / sys_exit so all  ~700 per-syscall
events expose the shared dispatcher prototype and record.
The per-syscall events do not own their own tracepoint
(they share sys_enter/sys_exit), so raw_btf_id is reported as 0
on those events; the meaningful raw_btf_id is exposed on
raw_syscalls/sys_{enter,exit}/btf_ids where raw_tp / tp_btf
programs can actually attach.

Link: https://patch.msgid.link/20260518-generic_tracepoint-v2-2-b755a5cf67bb@meta.com
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-28 07:18:48 -04:00
Linus Torvalds
864be1277d tracing fix for 7.2:
- Move rb_desc->nr_page_va before updating dynamic array
 
   The rb_descr->page_va is a dynamic array counted by nr_page_va. But the
   updating of the page_va[] is done before the nr_page_va is incremented
   causing a build with CONFIG_UBSAN_BOUNDS to flag it as an overflow.
 
   Move the increment of the counted by value before the array element is
   updated.
 
 - Propagate errors from remote event bulk updates
 
   The return value of trace_remote_enable_event() was not being checked by
   remote_events_dir_enable_write() where it would silently fail. Have it
   check the return value and propagate that back up to user space.
 
 - Fix resource leak on mmiotrace trace_pipe close
 
   The mmiotrace tracer was created in 2008 before the trace_pipe had a close
   callback to allow tracers to do clean up from trace_pipe open. The
   trace_pipe close cleanup callback was added in 2009 but the mmiotrace
   tracer was not updated. It had a hack to do the cleanup in the read call,
   where it may leak if user space did not read the entire buffer.
 
   Add a callback to mmiotrace trace_pipe close do to the cleanup properly.
 
 - Fix a possible NULL pointer dereference in the mmiotrace tracer
 
   If the mmio_pipe_open() fails to find a PCI device, it will set the
   hiter->dev pointer to NULL. The read function will blindly dereference
   that pointer. Fix the read call to check to see if that pointer is
   populated before dereferencing it.
 
 - Fix union collision of module and refcnt for dynamic events
 
   In 'struct trace_event_call', the 'module' pointer and the 'refcnt' atomic
   variable share the same memory space in a union. The filter on module
   logic only checked if the 'module' was set to determine if the event
   belonged to the module. As dynamic events are always builtin, it doesn't
   need the 'module' field of the structure and used a refcount. But the
   module filtering logic would then mistaken these dynamic events as a
   module and call module_name(event->module) on it.
 
   Add a check to see if the event is a dynamic event and if so, do not check
   it for being part of the given module.
 
 - Reset the top level buffer in selftests before running instances
 
   The ftracetest selftest initializes each instance before executing the
   tests. But it does not reset the top level buffer. Dynamic events are only
   added and removed by the top level so any left over dynamic events will
   not be removed by the reset in the instances.
 
   Left over dynamic events can cause the tests to incorrectly fail. Reset
   the top level buffer before running the instances.
 
 - Make the context_switch counter 64 bit
 
   The code to read user space for a system call trace event or for a
   trace_marker will disable migration, enable preemption, read user space
   into a per CPU buffer, disable preemption and enable migration again.
   It checks if the per CPU context switch counter to see if it changed, and
   if it did not, it would know that the per CPU buffer was not touched by
   another task.
 
   But the save counter was 32 bit and it would compare it to the 64 bit
   context_switch variable. A long running system could have the
   context_switch variable greater that 1<<32 in which case the compare will
   always fail. The compare will promote the 32 bit int saved value to 64 bit
   and compare it to the full 64 bit counter. Since the top 32 bits of the
   saved value was zero, it would never match.
 
 - Fix a use-after-free of the event_enable trigger
 
   The event_enable trigger allows for enabling one event when another event
   is triggered. When the trigger is removed, it must go through a
   synchronization phase to make sure it is not triggered again. The trigger
   itself is delayed by the "bulk delay" logic that was recently added.
   But the code that frees the event_enable data used to rely on the trigger
   code to do the synchronization. Now that the code uses the call RCU
   functions (and a workqueue), that delay no longer is there.
 
   Add a callback private_data_free() function that allows triggers to clean
   up data after the synchronization phase has completed.
 
 - Move the module_ref counter into the delay callback
 
   Since an event of the event_enable trigger can enable an event for a
   module, it ups the module ref count for that event's module. This prevents
   the event from trying to enable an event that no longer exists and cause a
   use-after-free bug.
 
   The ref counter was set back down when the trigger was removed but not
   after thy synchronization phase. This could lead to the module data being
   accessed after module was unloaded.
 
   Move the module ref decrement into the private_data_free() callback of the
   event_enable trigger.
 
 - Add mutex to protect parser in ftrace filtering
 
   The set_ftrace_filter file uses a parsing descriptor that is allocated at
   open and modified by writes. If multiple threads were to write to the
   descriptor at the same time, it can corrupt the parser.
 
   Add a mutex around the modifications of the parser descriptor.
 
 - Fix possible corruption in perf syscall tracing
 
   The perf system call trace events can now read user space. To do so, the
   reads of user space enable preemption and disables it again. During this
   time that preemption is enabled, the task can migrate. The perf event list
   head is assigned via a per CPU pointer. It is done before the user space
   part is called. If the user space reading migrates the task to another
   CPU, then the head pointer is no longer valid.
 
   Re-assign the head pointer after the reading of user space to keep it
   using the correct data.
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Merge tag 'trace-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Move rb_desc->nr_page_va before updating dynamic array

   The rb_descr->page_va is a dynamic array counted by nr_page_va. But
   the updating of the page_va[] is done before the nr_page_va is
   incremented causing a build with CONFIG_UBSAN_BOUNDS to flag it as an
   overflow.

   Move the increment of the counted by value before the array element
   is updated.

 - Propagate errors from remote event bulk updates

   The return value of trace_remote_enable_event() was not being checked
   by remote_events_dir_enable_write() where it would silently fail.
   Have it check the return value and propagate that back up to user
   space.

 - Fix resource leak on mmiotrace trace_pipe close

   The mmiotrace tracer was created in 2008 before the trace_pipe had a
   close callback to allow tracers to do clean up from trace_pipe open.
   The trace_pipe close cleanup callback was added in 2009 but the
   mmiotrace tracer was not updated. It had a hack to do the cleanup in
   the read call, where it may leak if user space did not read the
   entire buffer.

   Add a callback to mmiotrace trace_pipe close do to the cleanup
   properly.

 - Fix a possible NULL pointer dereference in the mmiotrace tracer

   If the mmio_pipe_open() fails to find a PCI device, it will set the
   hiter->dev pointer to NULL. The read function will blindly
   dereference that pointer. Fix the read call to check to see if that
   pointer is populated before dereferencing it.

 - Fix union collision of module and refcnt for dynamic events

   In 'struct trace_event_call', the 'module' pointer and the 'refcnt'
   atomic variable share the same memory space in a union. The filter on
   module logic only checked if the 'module' was set to determine if the
   event belonged to the module. As dynamic events are always builtin,
   it doesn't need the 'module' field of the structure and used a
   refcount. But the module filtering logic would then mistaken these
   dynamic events as a module and call module_name(event->module) on it.

   Add a check to see if the event is a dynamic event and if so, do not
   check it for being part of the given module.

 - Reset the top level buffer in selftests before running instances

   The ftracetest selftest initializes each instance before executing
   the tests. But it does not reset the top level buffer. Dynamic events
   are only added and removed by the top level so any left over dynamic
   events will not be removed by the reset in the instances.

   Left over dynamic events can cause the tests to incorrectly fail.
   Reset the top level buffer before running the instances.

 - Make the context_switch counter 64 bit

   The code to read user space for a system call trace event or for a
   trace_marker will disable migration, enable preemption, read user
   space into a per CPU buffer, disable preemption and enable migration
   again. It checks if the per CPU context switch counter to see if it
   changed, and if it did not, it would know that the per CPU buffer was
   not touched by another task.

   But the save counter was 32 bit and it would compare it to the 64 bit
   context_switch variable. A long running system could have the
   context_switch variable greater that 1<<32 in which case the compare
   will always fail. The compare will promote the 32 bit int saved value
   to 64 bit and compare it to the full 64 bit counter. Since the top 32
   bits of the saved value was zero, it would never match.

 - Fix a use-after-free of the event_enable trigger

   The event_enable trigger allows for enabling one event when another
   event is triggered. When the trigger is removed, it must go through a
   synchronization phase to make sure it is not triggered again. The
   trigger itself is delayed by the "bulk delay" logic that was recently
   added. But the code that frees the event_enable data used to rely on
   the trigger code to do the synchronization. Now that the code uses
   the call RCU functions (and a workqueue), that delay no longer is
   there.

   Add a callback private_data_free() function that allows triggers to
   clean up data after the synchronization phase has completed.

 - Move the module_ref counter into the delay callback

   Since an event of the event_enable trigger can enable an event for a
   module, it ups the module ref count for that event's module. This
   prevents the event from trying to enable an event that no longer
   exists and cause a use-after-free bug.

   The ref counter was set back down when the trigger was removed but
   not after thy synchronization phase. This could lead to the module
   data being accessed after module was unloaded.

   Move the module ref decrement into the private_data_free() callback
   of the event_enable trigger.

 - Add mutex to protect parser in ftrace filtering

   The set_ftrace_filter file uses a parsing descriptor that is
   allocated at open and modified by writes. If multiple threads were to
   write to the descriptor at the same time, it can corrupt the parser.

   Add a mutex around the modifications of the parser descriptor.

 - Fix possible corruption in perf syscall tracing

   The perf system call trace events can now read user space. To do so,
   the reads of user space enable preemption and disables it again.
   During this time that preemption is enabled, the task can migrate.
   The perf event list head is assigned via a per CPU pointer. It is
   done before the user space part is called. If the user space reading
   migrates the task to another CPU, then the head pointer is no longer
   valid.

   Re-assign the head pointer after the reading of user space to keep it
   using the correct data.

* tag 'trace-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: perf: Fix stale head for perf syscall tracing
  ftrace: Add global mutex to serialize trace_parser access
  tracing: Delay module ref count for "enable_event" trigger
  tracing: Fix use-after-free freeing trigger private data
  tracing: Fix context switch counter truncation
  selftests/ftrace: Reset triggers at top level before instance loop
  tracing: Fix union collision of module and refcnt for dynamic events
  tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev
  tracing: Fix resource leak on mmiotrace trace_pipe close
  tracing: Propagate errors from remote event bulk updates
  tracing/remotes: Fix page_va[] access before counter update in trace_remote_alloc_buffer()
2026-07-26 09:15:59 -07:00
Eduard Zingerman
4748a67f71 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 7.2-rc5
Cross-merge BPF and other fixes after downstream PR.

Conflicts:
	net/core/filter.c

Changes [2] in bpf-next conflict with a recent fix [1]
from the 'net' tree. Resolved by using [1] as a base and
applying same flags handling logic as in [2] in the
bpf_redirect_peer() helper.

[1] https://lore.kernel.org/all/20260706185609.330006-2-daniel@iogearbox.net/
[2] https://lore.kernel.org/all/20260618182035.43811-2-jordan@jrife.io/

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
2026-07-24 21:54:42 -07:00
Steven Rostedt
2c2b322acd tracing: perf: Fix stale head for perf syscall tracing
The code that can read the user space parameters of a system call may
enable preemption and migrate. The head of the per CPU perf events list
may be pointing to the wrong CPU event if the code migrates the task.

Reassign the head pointer if the system call event called the code that
may have caused a migration.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260724193210.03fae1d6@gandalf.local.home
Reported-by: Sashiko <>
Link: https://sashiko.dev/#/patchset/20260717173252.3431565-1-usama.arif%40linux.dev
Fixes: edca33a562 ("tracing: Fix failure to read user space from system call trace events")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 22:57:56 -04:00
Tengda Wu
7720b63bce ftrace: Add global mutex to serialize trace_parser access
In ftrace, the trace_parser structure is allocated and initialized when
a trace file is opened, and is subsequently used across write and release
handlers to parse user input.

The affected handler paths and their specific functions are:
  - Open paths: ftrace_regex_open(), ftrace_graph_open()
  - Write paths: ftrace_regex_write(), ftrace_graph_write()
  - Release paths: ftrace_regex_release(), ftrace_graph_release()

If userspace opens a trace file descriptor and shares it across multiple
threads, concurrent write calls will race on the parser's internal state,
specifically the 'idx', 'cont', and 'buffer' fields, leading to corrupted
input or undefined behavior.

Fix this by adding a global mutex, parser_lock, to serialize all access
to trace_parser across write and release paths, preventing concurrent
corruption of parser state.

Fixes: e704eff3ff ("ftrace: Have set_graph_function handle multiple functions in one write")
Fixes: 689fd8b65d ("tracing: trace parser support for function and graph")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260725024721.1983675-1-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 22:56:43 -04:00
Steven Rostedt
e091351b38 tracing: Delay module ref count for "enable_event" trigger
Triggers are now delayed from freeing, but can still be triggered until
after the RCU grace period has ended. The freeing of the enable_event data
is put into the private_data_free() callback, but the put of the module
refcount is done immediately.

It is possible that if a module is removed that has an event that would
enable (or disable) it is still active, it can read the data of the module
after it is removed causing a use-after-free bug.

Move the trace_event_put_ref() that releases the module into the delayed
callback so that the module can not be removed until any reference to its
events are finished.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260724132415.1b5005db@gandalf.local.home
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260724030523.19081-1-devnexen%40gmail.com
Fixes: 61d445af0a ("tracing: Add bulk garbage collection of freeing event_trigger_data")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 18:49:51 -04:00
David Carlier
7909781215 tracing: Fix use-after-free freeing trigger private data
Commit 61d445af0a ("tracing: Add bulk garbage collection of freeing
event_trigger_data") moved the kfree() of event_trigger_data to a kthread
that runs tracepoint_synchronize_unregister() before freeing. That removed
the synchronization the trigger .free callbacks used to get implicitly and
inline from trigger_data_free().

event_hist_trigger_free(), event_hist_trigger_named_free() and
event_enable_trigger_free() free their satellite data (hist_data, cmd_ops,
enable_data) right after trigger_data_free() returns. With the
synchronization now deferred to the kthread, a concurrent tracepoint
handler can still reach that data through the list_del_rcu()'d trigger,
causing a use-after-free.

The histogram teardown must stay synchronous: remove_hist_vars() and
unregister_field_var_hists() have to detach a synthetic event from the
histogram before the trigger-removal write returns, otherwise a following
command races in and the synthetic-event removal fails with -EBUSY, as the
trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait
with the correct barrier - tracepoint_synchronize_unregister(), matching
the free kthread - before freeing.

The enable trigger has no such synchronous requirement, and a blocking
synchronize there would re-serialize the path that commit deliberately
deferred. Give it an optional private_data_free() callback that the free
kthread runs after its grace period, and free enable_data from there.

Link: https://patch.msgid.link/20260724030523.19081-1-devnexen@gmail.com
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 61d445af0a ("tracing: Add bulk garbage collection of freeing event_trigger_data")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 18:49:51 -04:00
Usama Arif
8f76afb9b1 tracing: Fix context switch counter truncation
trace_user_fault_read() samples nr_context_switches_cpu() before enabling
preemption and retries the user copy if the counter changes. The helper
returns unsigned long long because rq->nr_switches is u64, but the saved
value is unsigned int.

Once a CPU has performed 2^32 context switches, assigning the counter to
cnt discards its upper bits. The comparison after the copy promotes cnt
back to unsigned long long, but the lost bits remain zero, so it reports a
change even when the task was never scheduled out. Every retry then fails
the same way until the 100-try guard warns and the user copy is abandoned.

This affects long-running systems and workloads with high context-switch
rates. A CPU switching 1,000 times per second takes about 50 days.

Store the sampled count in unsigned long long so the full value is
preserved.

Cc: stable@vger.kernel.org
Fixes: 64cf7d058a ("tracing: Have trace_marker use per-cpu data to read user space")
Link: https://patch.msgid.link/20260717173252.3431565-1-usama.arif@linux.dev
Reported-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Usama Arif <usama.arif@linux.dev>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 13:43:18 -04:00
Masami Hiramatsu (Google)
b4eb07bde6 tracing: Fix union collision of module and refcnt for dynamic events
In 'struct trace_event_call', the 'module' pointer and the 'refcnt'
atomic variable share the same memory space in a union. For dynamic
events, the union member is 'refcnt', which acts as an active
reference counter.

When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or
wprobe) has a non-zero reference count (e.g. due to active event
triggers or perf attachments), its 'call->module' evaluates to a
small non-zero integer instead of NULL.

When filtering or setting events for a specific module (e.g., writing
':mod:<module>' to 'set_event'), the code in
'__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads
'call->module' directly without checking whether the event is dynamic.
This causes the kernel to treat the small integer (refcnt) as a
'struct module' pointer, leading to a NULL/invalid pointer dereference
(Oops) when dereferencing the module name.

Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked
before treating 'call->module' as a valid pointer in these code paths.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178425670947.84440.11344393611899824907.stgit@devnote2
Fixes: 4c86bc531e ("tracing: Add :mod: command to enabled module events")
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 13:43:17 -04:00
Steven Rostedt
144f29e857 tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev
If the mmio_pipe_open() fails to find a PCI device, the hiter->dev
will be assigned to NULL. The mmiotrace read() function dereferences the
hiter->dev if hiter exists.

Change the test of the read to not only check hiter being NULL, but also
the hiter->dev before dereferencing it.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260721211143.36dbd559@gandalf.local.home
Fixes: f984b51e07 ("ftrace: add mmiotrace plugin")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260715143604.14481-1-gaikwad.dcg%40gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-24 13:43:09 -04:00
Nam Cao
6fdaab4e16 rv/rtapp: Add wakeup monitor
Add a wakeup monitor to detect a lower-priority task waking up a
higher-priority task.

The rtapp/sleep monitor already detects this. However, that monitor
triggers an error in the context of the wakee task and user only gets
the stacktrace of that task. It is also extremely useful to get the
stacktrace of the waker task, which this monitor offers. In other
words, this monitor complements the rtapp/sleep monitor.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/ba5658fa13e49ada466b84a2c211f233037180b5.1781852967.git.namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24 09:01:10 +02:00
Nam Cao
28e68d3cdc rv/rtapp/sleep: Stop monitoring kernel threads
The rtapp/sleep monitor's primary purpose is detecting common mistakes
with user-space real-time design. Monitoring real-time issues with
kernel threads is a bonus.

However, accomodating kernel threads complicates the monitor due to
the edge cases which is seen by the monitor as lower-priority task
waking higher-priority task:

  - kthread_stop() wakes up the task in order to stop it.

  - The rcu thread and migration thread can be woken by any task.

  - The ktimerd thread is woken near the end of irq_exit_rcu(), where
    the preempt counter is "broken" and falsely says this is task
    context. This requires the monitor to use the hardirq_context flag
    instead of the preempt counter.

Beside complicating the monitor, the final case also requires enabling
CONFIG_TRACE_IRQFLAGS (so that "hardirq_context" can be used). This
adds overhead to the kernel even when the monitor is not active. This
may be an obstacle to enabling this monitor in distros' kernels.

Furthermore, kernel threads usually are started before the monitor is
enabled. Consequently, the threads' states (i.o.w. the monitor's
atomic propositions for the threads) are not fully known to the
monitor. As a result, the kernel threads mostly cannot be monitored.

Overall, the downsides of accomodating kernel threads outweights the
benefits. Thus, exclude kernel threads to simplify the monitor.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/eec2ca5224bcdacc45b8e1eb2f0e68109e1cae7a.1781852967.git.namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24 09:01:10 +02:00
Nam Cao
8fc4e16c75 rv/rtapp/sleep: Update nanosleep rule
CLOCK_REALTIME is the only clock that often is misused in real-time
applications. The other clocks either are safe for real-time uses
(CLOCK_TAI, CLOCK_MONOTONIC, CLOCK_BOOTTIME) or are unlikely to be misused
(CLOCK_AUX, CLOCK_PROCESS_CPUTIME_ID).

Update the monitor to only warn about CLOCK_REALTIME.

While at it, update the out-of-sync documentation.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/c7ceb5c6263ee8f43a2676acae669cf486b0d903.1781852967.git.namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24 09:01:10 +02:00
Nam Cao
42545589e3 rv/rtapp/sleep: Make the error more informative for user
The rtapp/sleep monitor detects real-time tasks which go to sleep in an
real-time-unsafe manner. If this happen, the monitor triggers a trace event
in the sched_wakeup tracepoint's handler.

However, the invoking context of that trace event is not the most
informative, because of the stack trace of that event is the wakeup's code
path which is not very helpful:

74.669317: rv:error_sleep: condvar[254]: violation detected
    ltl_validate+0x345 ([kernel.kallsyms])
    handle_sched_wakeup+0x34 ([kernel.kallsyms])
    ttwu_do_activate+0xff ([kernel.kallsyms])
    sched_ttwu_pending+0x104 ([kernel.kallsyms])
    __flush_smp_call_function_queue+0x15b ([kernel.kallsyms])
    __sysvec_call_function_single+0x18 ([kernel.kallsyms])
    sysvec_call_function_single+0x66 ([kernel.kallsyms])
    asm_sysvec_call_function_single+0x1a ([kernel.kallsyms])
    pv_native_safe_halt+0xf ([kernel.kallsyms])
    default_idle+0x9 ([kernel.kallsyms])
    default_idle_call+0x33 ([kernel.kallsyms])
    do_idle+0x234 ([kernel.kallsyms])
    cpu_startup_entry+0x24 ([kernel.kallsyms])
    start_secondary+0xf8 ([kernel.kallsyms])
    common_startup_64+0x13e ([kernel.kallsyms])

What would be much more valuable is the stack trace of the task itself.

Instead of using the sched_wakeup tracepoint, use the sched_exit
tracepoint. This makes the event happen in the task's context, making
the stack trace far more informative for user:

rv:error_sleep: condvar[254]: violation detected
    ltl_validate+0x345 ([kernel.kallsyms])
    handle_sched_exit+0x39 ([kernel.kallsyms])
    __schedule+0x80f ([kernel.kallsyms])
    schedule+0x22 ([kernel.kallsyms])
    futex_do_wait+0x33 ([kernel.kallsyms])
    __futex_wait+0x8c ([kernel.kallsyms])
    futex_wait+0x73 ([kernel.kallsyms])
    do_futex+0xc6 ([kernel.kallsyms])
    __x64_sys_futex+0x121 ([kernel.kallsyms])
    do_syscall_64+0xf3 ([kernel.kallsyms])
    entry_SYSCALL_64_after_hwframe+0x77 ([kernel.kallsyms])
    __futex_abstimed_wait_common64+0xc6 (inlined)
    __futex_abstimed_wait_common+0xc6 (/usr/lib/x86_64-linux-gnu/libc.so.6)

Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/d97b4b5c476e5792b6875ec9bbf8dc214f999516.1781852967.git.namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-24 09:01:10 +02:00
deepakraog
c1d87e724a tracing: Fix resource leak on mmiotrace trace_pipe close
The mmiotrace tracer was added May 12th 2008. At that time, resources
created in pipe_open() could not be freed because there was not
pipe_close function pointer of the tracer. The pipe_close function pointer
was added in December 7th, 2009, but the mmiotrace tracer was not updated.

mmio_pipe_open() allocates a header_iter and takes a pci_dev reference
when trace_pipe is opened. mmio_close() frees them, but it was only
wired to the tracer's .close callback.

tracing_release_pipe() invokes .pipe_close, not .close, when the
trace_pipe file is released. As a result, closing trace_pipe with the
mmiotrace tracer active leaked the header_iter allocation and left a
stale pci_dev reference.

Set .pipe_close to mmio_close, matching how function_graph wires both
callbacks to the same handler.

Note, if the trace_pipe is read to completion, it will clean up the
resources, but if one were to run:

  # head -n 1 /sys/kernel/tracing/trace_pipe
 VERSION 20070824

Over and over again, it would trigger a massive leak.

Cc: stable@vger.kernel.org
Fixes: c521efd170 ("tracing: Add pipe_close interface)
Link: https://patch.msgid.link/20260715143604.14481-1-gaikwad.dcg@gmail.com
Signed-off-by: deepakraog <gaikwad.dcg@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-23 12:30:07 -04:00
Jackie Liu
655111f878 tracing: Propagate errors from remote event bulk updates
remote_events_dir_enable_write() ignores the return value from
trace_remote_enable_event(). If a remote rejects an event state change,
the write therefore reports success even though the affected event remains
in its previous state.

Keep trying all events, but retain and return the first error. This matches
__ftrace_set_clr_event_nolock(), which permits partial updates while
notifying userspace when an operation fails.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260715074455.3897-1-liu.yun@linux.dev
Fixes: 775cb093bc ("tracing: Add events/ root files to trace remotes")
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-23 12:30:07 -04:00
Li Qiang
b255fc56f4 rv: Simplify task monitor slot management
The slot array already tracks allocation and task_monitor_count
duplicates that state. On an invalid second release, the old code
warns but still decrements the counter, corrupting later allocations.

Use the slot array as the sole source of truth. Return after warning
about an unused slot, and return -EBUSY when no slot is free.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Li Qiang <liqiang01@kylinos.cn>
Link: https://lore.kernel.org/r/20260715015825.1413822-1-liqiang01@kylinos.cn
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-07-23 13:38:23 +02:00
Fuad Tabba
94b83ff0c0 tracing/remotes: Fix page_va[] access before counter update in trace_remote_alloc_buffer()
page_va[] is annotated __counted_by(nr_page_va), so nr_page_va must
cover an index before that element is accessed. The allocation loop
writes page_va[id] while nr_page_va is still id and increments it only
afterwards, so every write is one element past the declared count.

The store is out of bounds with respect to the annotation: a build with
CONFIG_UBSAN_BOUNDS on a toolchain that honours __counted_by
(clang >= 20.1, gcc >= 15.1) flags it as an array-index overflow.

Increment nr_page_va before writing the element it now covers. A failed
allocation then leaves the slot counted but NULL; the error path frees
it with free_page(0), which is a no-op.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260713072823.2668323-1-fuad.tabba@linux.dev
Fixes: 96e43537af ("tracing: Introduce trace remotes")
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-07-22 16:53:29 -04:00
Masami Hiramatsu (Google)
5be3a9db60 tracing/probes: Fix extra whitespace in trace_probe_kernel.h
Clean up extra space after '=' in fetch_store_strlen_user().

Link: https://lore.kernel.org/all/178454430235.296567.9486503882045148585.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 18:00:13 +09:00
Masami Hiramatsu (Google)
5b385fd434 tracing/kprobe: Remove redundant memset in kprobe_perf_func()
kprobe_perf_func() calls memset(&entry[1], 0, dsize) prior to calling
store_trace_args(). store_trace_args() populates the entry buffer and
handles dynamic data fields.

Remove this redundant memset call to align with kretprobe_perf_func() and
other probe perf functions.

Link: https://lore.kernel.org/all/178454429309.296567.17379087988750549247.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 18:00:09 +09:00
Masami Hiramatsu (Google)
3d785646cc tracing/fprobe: Remove redundant memset in fentry_perf_func()
fentry_perf_func() calls memset(&entry[1], 0, dsize) prior to calling
store_trace_args(). store_trace_args() populates the entry buffer and
handles dynamic data fields.

Furthermore, passing dsize (the dynamic data byte length) to memset at
&entry[1] (the start of fixed trace arguments) is inaccurate as it zeroes
from the fixed args area rather than the dynamic data region.

Remove this redundant memset call to align with fexit_perf_func() and other
probe perf functions.

Link: https://lore.kernel.org/all/178454428366.296567.16465331441301815980.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 18:00:05 +09:00
Masami Hiramatsu (Google)
36db65d0e5 tracing/fprobe: Remove redundant snprintf in trace_fprobe_match_command_head()
trace_fprobe_match_command_head() copies trace_fprobe_symbol(tf) into a
local buffer 'buf' of size MAX_COMMON_HEAD_LEN + 1 using snprintf before
comparing with argv[0].

Since trace_fprobe_symbol(tf) already returns a null-terminated string,
comparing it directly with argv[0] via strcmp() avoids stack buffer usage
and potential symbol truncation at MAX_COMMON_HEAD_LEN.

Link: https://lore.kernel.org/all/178454427449.296567.12336315661120939938.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 18:00:01 +09:00
Masami Hiramatsu (Google)
0fb6fd1eb3 tracing/probes: Simplify BTF_KIND_PTR case in fetch_type_from_btf_type()
Use a ternary operator for checking IS_ENABLED(CONFIG_64BIT) in the
BTF_KIND_PTR case of fetch_type_from_btf_type() to simplify the code.

Link: https://lore.kernel.org/all/178454426554.296567.17700307233923830044.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 17:59:58 +09:00
Masami Hiramatsu (Google)
78d252c935 tracing/probes: Cleanup pointer arithmetic in store_trace_entry_data()
In store_trace_entry_data(), edata is cast to unsigned long for pointer
offset arithmetic before being cast back to unsigned long *. Cast edata
to u8 * instead.

Link: https://lore.kernel.org/all/178454425622.296567.16952341966130280432.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 17:59:54 +09:00
Masami Hiramatsu (Google)
5428fca0cd tracing/probes: Remove unused parameter from parse_probe_var_retval()
The parameter 'arg' in parse_probe_var_retval() is unused. Remove it
and update its caller accordingly.

Link: https://lore.kernel.org/all/178454424711.296567.15352344258939682112.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 17:59:50 +09:00
Masami Hiramatsu (Google)
6e9328ed75 tracing/probes: Remove redundant bounds check in trace_probe_compare_arg_type()
In trace_probe_compare_arg_type(), prior to entering the comparison loop,
a->nr_args and b->nr_args are checked for equality. Since the loop
condition is i < a->nr_args, i is guaranteed to be less than b->nr_args
inside the loop.

Remove the redundant (b->nr_args <= i) check.

Link: https://lore.kernel.org/all/178454423769.296567.6694636865644203423.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-07-21 17:59:46 +09:00