The per-cpu object checksum folds each CPU's CRC together with XOR and
seeds every CRC with 0. Both choices make update_checksum() miss content
changes:
- XOR is self-cancelling, so equal contents on two CPUs cancel out and
simultaneous identical changes leave the checksum unchanged.
- crc32(0, ...) over all-zero content is 0, so a freshly allocated,
zeroed per-cpu area checksums to 0, matching the initial value, and
the object is never seen to change.
See discussions at [0].
When update_checksum() wrongly reports an actively modified object as
unchanged, kmemleak stops greying it for an extra scan and can report a
live per-cpu object as a leak.
Fold the per-cpu CRC as a single rolling checksum across all CPUs and
initialise the object checksum to ~0 so the first computed value always
registers as a change, even for content that hashes to 0.
reset_checksum() is seeded the same way.
Link: https://lore.kernel.org/all/akfYImSNDh3OjIfR@gmail.com [0]
Link: https://lore.kernel.org/20260703-kmemleak_checksum-v1-1-5e0ab7d6966f@debian.org
Fixes: 6c99d4eb7c ("kmemleak: enable tracking for percpu pointers")
Signed-off-by: Breno Leitao <leitao@debian.org>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/kmemleak: dedupe verbose scan output", v3.
I am starting to run with kmemleak in verbose enabled in some "probe
points" across the my employers fleet so that suspected leaks land in
dmesg without needing a separate read of /sys/kernel/debug/kmemleak.
The downside is that workloads which leak many objects from a single
allocation site flood the console with byte-for-byte identical backtraces.
Hundreds of duplicates per scan are common, drowning out distinct leaks
and unrelated kernel messages, while adding no signal beyond the first
occurrence.
This series collapses those duplicates inside kmemleak itself. Each
unique stackdepot trace_handle prints once per scan, followed by a short
summary line when more than one object shares it:
kmemleak: unreferenced object 0xff110001083beb00 (size 192):
kmemleak: comm "modprobe", pid 974, jiffies 4294754196
kmemleak: ...
kmemleak: backtrace (crc 6f361828):
kmemleak: __kmalloc_cache_noprof+0x1af/0x650
kmemleak: ...
kmemleak: ... and 71 more object(s) with the same backtrace
The "N new suspected memory leaks" tally and the contents of
/sys/kernel/debug/kmemleak are unchanged - the per-object detail is still
available on demand, only the verbose (dmesg) output is collapsed.
Patch 1 is the kmemleak change.
Patch 2 adds a selftest that loads samples/kmemleak's CONFIG_SAMPLE
kmemleak-test module to generate ten leaks sharing one call site and
checks that the printed count is strictly less than the reported leak
total. Not sure if Patch 2 is useful or not, if not, it is easier to
discard.
This patch (of 2):
In kmemleak's verbose mode, every unreferenced object found during a scan
is logged with its full header, hex dump and 16-frame backtrace.
Workloads that leak many objects from a single allocation site flood dmesg
with byte-for-byte identical backtraces, drowning out distinct leaks and
other kernel messages.
Dedupe within each scan using stackdepot's trace_handle as the key: for
every leaked object with a recorded stack trace, look up the
representative kmemleak_object in a per-scan xarray keyed by trace_handle.
The first sighting stores the object pointer (with a get_object()
reference) and sets object->dup_count to 1; later sightings just bump
dup_count on the representative. After the scan, walk the xarray once and
emit each unique backtrace, followed by a single summary line when more
than one object shares it.
Leaks whose trace_handle is 0 (early-boot allocations tracked before
kmemleak_init() set up object_cache, or stack_depot_save() failures under
memory pressure) cannot be deduped, so they are still printed inline via
the same locked OBJECT_ALLOCATED-checked helper. The contents of
/sys/kernel/debug/kmemleak are unchanged - only the verbose console output
is collapsed.
Safety notes:
- The xarray store happens outside object->lock: object->lock is a
raw spinlock, while xa_store() may grab xa_node slab locks at a
higher wait-context level which lockdep flags as invalid.
trace_handle is captured under object->lock (which serialises with
kmemleak_update_trace()'s writer), so it is safe to use after
dropping the lock.
- get_object() pins the kmemleak_object metadata across
rcu_read_unlock(), but the underlying tracked allocation can still
be freed concurrently. The deferred print path therefore re-acquires
object->lock and re-checks OBJECT_ALLOCATED via print_leak_locked()
before touching object->pointer; __delete_object() clears that flag
under the same lock before the user memory goes away. The same
helper is used by the trace_handle == 0 and xa_store() failure
fallbacks, so every printer in the new path has identical safety
guarantees.
- If get_object() fails after we set OBJECT_REPORTED, the object is
already being torn down (use_count hit zero); the leak count is
still accurate but the verbose line is dropped, which is correct
- the memory was freed concurrently and is no longer a leak.
- If xa_store() fails to allocate an xa_node under memory pressure,
we fall back to printing inline via print_leak_locked() instead of
silently dropping the leak.
- The hex dump is skipped for coalesced entries (dup_count > 1):
bytes would differ across objects sharing a backtrace anyway, and
skipping it removes the only remaining read of object->pointer's
contents in the deferred path. The representative's reported size
may also differ from the coalesced objects' sizes; the printed
trace_handle reflects the representative's current value rather
than the value used as the dedup key, which is normally - but not
strictly - identical.
Link: https://lore.kernel.org/20260506-kmemleak_dedup-v3-0-2d36aafc34da@debian.org
Link: https://lore.kernel.org/20260506-kmemleak_dedup-v3-1-2d36aafc34da@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a Kconfig option to default kmemleak verbose mode on at build time.
This option depends on DEBUG_KMEMLEAK_AUTO_SCAN since verbose reporting is
only meaningful when the automatic scanning thread is running.
When enabled, kmemleak prints full details (backtrace, hex dump, address)
of unreferenced objects to dmesg as they are detected during scanning,
removing the need to manually read /sys/kernel/debug/kmemleak.
Making this a compile-time option rather than a boot parameter allows
debug kernel flavors to enable verbose kmemleak reporting by default
without requiring changes to boot arguments. A machine can simply swap to
a debug kernel and benefit from kmemleak reporting automatically.
By surfacing leak reports directly in dmesg, they are automatically
forwarded through any kernel logging infrastructure and can be easily
captured by log aggregation tooling, making it practical to monitor memory
leaks across large fleets.
The verbose setting can still be toggled at runtime via
/sys/module/kmemleak/parameters/verbose.
Link: https://lore.kernel.org/20260323-kmemleak_report-v1-1-ba2cdd9c11b9@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace the current->mm check with PF_KTHREAD flag for more reliable
kernel thread detection in scan_should_stop(). The PF_KTHREAD flag is the
standard way to identify kernel threads and is not affected by temporary
mm borrowing via kthread_use_mm() (although kmemleak does not currently
encounter such cases, this makes the code more robust).
No functional change.
Link: https://lkml.kernel.org/r/20260130093729.2045858-3-zhongqiu.han@oss.qualcomm.com
Signed-off-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/kmemleak: Improve scan_should_stop() implementation".
This series improves the scan_should_stop() function by addressing code
quality issues and enhancing kernel thread detection robustness.
This patch (of 2):
Remove unreachable "return 0;" statement as all execution paths return
before reaching it.
No functional change.
Link: https://lkml.kernel.org/r/20260130093729.2045858-2-zhongqiu.han@oss.qualcomm.com
Signed-off-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge tag 'slab-for-7.0-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull more slab updates from Vlastimil Babka:
- Two stable fixes for kmalloc_nolock() usage from NMI context (Harry
Yoo)
- Allow kmalloc_nolock() allocations to be freed with kfree() and thus
also kfree_rcu() and simplify slabobj_ext handling - we no longer
need to track how it was allocated to use the matching freeing
function (Harry Yoo)
* tag 'slab-for-7.0-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm/slab: drop the OBJEXTS_NOSPIN_ALLOC flag from enum objext_flags
mm/slab: allow freeing kmalloc_nolock()'d objects using kfree[_rcu]()
mm/slab: use prandom if !allow_spin
mm/slab: do not access current->mems_allowed_seq if !allow_spin
Slab objects that are allocated with kmalloc_nolock() must be freed
using kfree_nolock() because only a subset of alloc hooks are called,
since kmalloc_nolock() can't spin on a lock during allocation.
This imposes a limitation: such objects cannot be freed with kfree_rcu(),
forcing users to work around this limitation by calling call_rcu()
with a callback that frees the object using kfree_nolock().
Remove this limitation by teaching kmemleak to gracefully ignore cases
when kmemleak_free() or kmemleak_ignore() is called without a prior
kmemleak_alloc().
Unlike kmemleak, kfence already handles this case, because,
due to its design, only a subset of allocations are served from kfence.
With this change, kfree() and kfree_rcu() can be used to free objects
that are allocated using kmalloc_nolock().
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260210044642.139482-2-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
There aren't any bugs in this code; it's purely cosmetic.
By using ARRAY_END(), we prevent future issues, in case the code is
modified; it has less moving parts. Also, it should be more readable (and
perhaps more importantly, greppable), as there are several ways of writing
an expression that gets the end of an array, which are unified by this API
name.
Link: https://lkml.kernel.org/r/2335917d123891fec074ab1b3acfb517cf14b5a7.1765449750.git.alx@kernel.org
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christopher Bazley <chris.bazley.wg14@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are some AA deadlock issues in kmemleak, similar to the situation
reported by Breno [1]. The deadlock path is as follows:
mem_pool_alloc()
-> raw_spin_lock_irqsave(&kmemleak_lock, flags);
-> pr_warn()
-> netconsole subsystem
-> netpoll
-> __alloc_skb
-> __create_object
-> raw_spin_lock_irqsave(&kmemleak_lock, flags);
To solve this problem, switch to printk_safe mode before printing warning
message, this will redirect all printk()-s to a special per-CPU buffer,
which will be flushed later from a safe context (irq work), and this
deadlock problem can be avoided. The proper API to use should be
printk_deferred_enter()/printk_deferred_exit() [2]. Another way is to
place the warn print after kmemleak is released.
Link: https://lkml.kernel.org/r/20250822073541.1886469-1-gubowen5@huawei.com
Link: https://lore.kernel.org/all/20250731-kmemleak_lock-v1-1-728fd470198f@debian.org/#t [1]
Link: https://lore.kernel.org/all/5ca375cd-4a20-4807-b897-68b289626550@redhat.com/ [2]
Signed-off-by: Gu Bowen <gubowen5@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Lu Jialin <lujialin4@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A soft lockup warning was observed on a relative small system x86-64
system with 16 GB of memory when running a debug kernel with kmemleak
enabled.
watchdog: BUG: soft lockup - CPU#8 stuck for 33s! [kworker/8:1:134]
The test system was running a workload with hot unplug happening in
parallel. Then kemleak decided to disable itself due to its inability to
allocate more kmemleak objects. The debug kernel has its
CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE set to 40,000.
The soft lockup happened in kmemleak_do_cleanup() when the existing
kmemleak objects were being removed and deleted one-by-one in a loop via a
workqueue. In this particular case, there are at least 40,000 objects
that need to be processed and given the slowness of a debug kernel and the
fact that a raw_spinlock has to be acquired and released in
__delete_object(), it could take a while to properly handle all these
objects.
As kmemleak has been disabled in this case, the object removal and
deletion process can be further optimized as locking isn't really needed.
However, it is probably not worth the effort to optimize for such an edge
case that should rarely happen. So the simple solution is to call
cond_resched() at periodic interval in the iteration loop to avoid soft
lockup.
Link: https://lkml.kernel.org/r/20250728190248.605750-1-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When netpoll is enabled, calling pr_warn_once() while holding
kmemleak_lock in mem_pool_alloc() can cause a deadlock due to lock
inversion with the netconsole subsystem. This occurs because
pr_warn_once() may trigger netpoll, which eventually leads to
__alloc_skb() and back into kmemleak code, attempting to reacquire
kmemleak_lock.
This is the path for the deadlock.
mem_pool_alloc()
-> raw_spin_lock_irqsave(&kmemleak_lock, flags);
-> pr_warn_once()
-> netconsole subsystem
-> netpoll
-> __alloc_skb
-> __create_object
-> raw_spin_lock_irqsave(&kmemleak_lock, flags);
Fix this by setting a flag and issuing the pr_warn_once() after
kmemleak_lock is released.
Link: https://lkml.kernel.org/r/20250731-kmemleak_lock-v1-1-728fd470198f@debian.org
Fixes: c566586818 ("mm: kmemleak: use the memory pool for early allocations")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reported-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When loading a module, as long as the module has memory allocation
operations, kmemleak produces a false positive report that resembles the
following:
unreferenced object (percpu) 0x7dfd232a1650 (size 16):
comm "modprobe", pid 1301, jiffies 4294940249
hex dump (first 16 bytes on cpu 2):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 0):
kmemleak_alloc_percpu+0xb4/0xd0
pcpu_alloc_noprof+0x700/0x1098
load_module+0xd4/0x348
codetag_module_init+0x20c/0x450
codetag_load_module+0x70/0xb8
load_module+0xef8/0x1608
init_module_from_file+0xec/0x158
idempotent_init_module+0x354/0x608
__arm64_sys_finit_module+0xbc/0x150
invoke_syscall+0xd4/0x258
el0_svc_common.constprop.0+0xb4/0x240
do_el0_svc+0x48/0x68
el0_svc+0x40/0xf8
el0t_64_sync_handler+0x10c/0x138
el0t_64_sync+0x1ac/0x1b0
This is because the module can only indirectly reference
alloc_tag_counters through the alloc_tag section, which misleads kmemleak.
However, we don't have a kmemleak ignore interface for percpu allocations
yet. So let's create one and invoke it for tag->counters.
[gehao@kylinos.cn: fix build error when CONFIG_DEBUG_KMEMLEAK=n, s/igonore/ignore/]
Link: https://lkml.kernel.org/r/20250620093102.2416767-1-hao.ge@linux.dev
Link: https://lkml.kernel.org/r/20250619183154.2122608-1-hao.ge@linux.dev
Fixes: 12ca42c237 ("alloc_tag: allocate percpu counters for module tags dynamically")
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Suren Baghdasaryan <surenb@google.com> [lib/alloc_tag.c]
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The variables kmemleak_enabled and kmemleak_free_enabled are read in the
kmemleak alloc and free path respectively, but are only written to if/when
kmemleak is disabled.
Link: https://lkml.kernel.org/r/4016090e857e8c4c2ade4b20df312f7f38325c15.1746046744.git.luizcap@redhat.com
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Newly created objects have object->count == 0, so the comment is
incorrect. Just drop it.
Link: https://lkml.kernel.org/r/3dfd09bc0e77bb626619184a808774ff07de275c.1746046744.git.luizcap@redhat.com
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: kmemleak: Usability improvements".
Following a recent false positive tracking that led to commit 488b5b9eca
("mm: kmemleak: fix upper boundary check for physical address objects"), I
needed kmemleak to give me more debug information about the objects it is
tracking. This lead to the first patch of this series. The second patch
changes the kmemleak-test module to show the raw pointers for debugging
purposes.
This patch (of 2):
Currently, echo dump=... > /sys/kernel/debug/kmemleak only looks up the
main virtual address object tree. However, for debugging, it's useful to
dump information about physical address and __percpu objects.
Search all three object trees for the dump= command and also print the
type of the object if not virtual: "(phys)" or "(percpu)". In addition,
allow search by alias (pointer within the object).
Link: https://lkml.kernel.org/r/20250206114537.2597764-1-catalin.marinas@arm.com
Link: https://lkml.kernel.org/r/20250206114537.2597764-2-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Memblock allocations are registered by kmemleak separately, based on their
physical address. During the scanning stage, it checks whether an object
is within the min_low_pfn and max_low_pfn boundaries and ignores it
otherwise.
With the recent addition of __percpu pointer leak detection (commit
6c99d4eb7c ("kmemleak: enable tracking for percpu pointers")), kmemleak
started reporting leaks in setup_zone_pageset() and
setup_per_cpu_pageset(). These were caused by the node_data[0] object
(initialised in alloc_node_data()) ending on the PFN_PHYS(max_low_pfn)
boundary. The non-strict upper boundary check introduced by commit
84c3262991 ("mm: kmemleak: check physical address when scan") causes the
pg_data_t object to be ignored (not scanned) and the __percpu pointers it
contains to be reported as leaks.
Make the max_low_pfn upper boundary check strict when deciding whether to
ignore a physical address object and not scan it.
Link: https://lkml.kernel.org/r/20250127184233.2974311-1-catalin.marinas@arm.com
Fixes: 84c3262991 ("mm: kmemleak: check physical address when scan")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Cc: <stable@vger.kernel.org> [6.0.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
this pull are:
- "lib min_heap: Improve min_heap safety, testing, and documentation"
from Kuan-Wei Chiu provides various tightenings to the min_heap library
code.
- "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms some
cleanup and Rust preparation in the xarray library code.
- "Update reference to include/asm-<arch>" from Geert Uytterhoeven fixes
pathnames in some code comments.
- "Converge on using secs_to_jiffies()" from Easwar Hariharan uses the
new secs_to_jiffies() in various places where that is appropriate.
- "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
switches two filesystems to the new mount API.
- "Convert ocfs2 to use folios" from Matthew Wilcox does that.
- "Remove get_task_comm() and print task comm directly" from Yafang Shao
removes now-unneeded calls to get_task_comm() in various places.
- "squashfs: reduce memory usage and update docs" from Phillip Lougher
implements some memory savings in squashfs and performs some
maintainability work.
- "lib: clarify comparison function requirements" from Kuan-Wei Chiu
tightens the sort code's behaviour and adds some maintenance work.
- "nilfs2: protect busy buffer heads from being force-cleared" from
Ryusuke Konishi fixes an issues in nlifs when the fs is presented with a
corrupted image.
- "nilfs2: fix kernel-doc comments for function return values" from
Ryusuke Konishi fixes some nilfs kerneldoc.
- "nilfs2: fix issues with rename operations" from Ryusuke Konishi
addresses some nilfs BUG_ONs which syzbot was able to trigger.
- "minmax.h: Cleanups and minor optimisations" from David Laight
does some maintenance work on the min/max library code.
- "Fixes and cleanups to xarray" from Kemeng Shi does maintenance work
on the xarray library code.
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Merge tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
"Mainly individually changelogged singleton patches. The patch series
in this pull are:
- "lib min_heap: Improve min_heap safety, testing, and documentation"
from Kuan-Wei Chiu provides various tightenings to the min_heap
library code
- "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms
some cleanup and Rust preparation in the xarray library code
- "Update reference to include/asm-<arch>" from Geert Uytterhoeven
fixes pathnames in some code comments
- "Converge on using secs_to_jiffies()" from Easwar Hariharan uses
the new secs_to_jiffies() in various places where that is
appropriate
- "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
switches two filesystems to the new mount API
- "Convert ocfs2 to use folios" from Matthew Wilcox does that
- "Remove get_task_comm() and print task comm directly" from Yafang
Shao removes now-unneeded calls to get_task_comm() in various
places
- "squashfs: reduce memory usage and update docs" from Phillip
Lougher implements some memory savings in squashfs and performs
some maintainability work
- "lib: clarify comparison function requirements" from Kuan-Wei Chiu
tightens the sort code's behaviour and adds some maintenance work
- "nilfs2: protect busy buffer heads from being force-cleared" from
Ryusuke Konishi fixes an issues in nlifs when the fs is presented
with a corrupted image
- "nilfs2: fix kernel-doc comments for function return values" from
Ryusuke Konishi fixes some nilfs kerneldoc
- "nilfs2: fix issues with rename operations" from Ryusuke Konishi
addresses some nilfs BUG_ONs which syzbot was able to trigger
- "minmax.h: Cleanups and minor optimisations" from David Laight does
some maintenance work on the min/max library code
- "Fixes and cleanups to xarray" from Kemeng Shi does maintenance
work on the xarray library code"
* tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits)
ocfs2: use str_yes_no() and str_no_yes() helper functions
include/linux/lz4.h: add some missing macros
Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent
Xarray: remove repeat check in xas_squash_marks()
Xarray: distinguish large entries correctly in xas_split_alloc()
Xarray: move forward index correctly in xas_pause()
Xarray: do not return sibling entries from xas_find_marked()
ipc/util.c: complete the kernel-doc function descriptions
gcov: clang: use correct function param names
latencytop: use correct kernel-doc format for func params
minmax.h: remove some #defines that are only expanded once
minmax.h: simplify the variants of clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: update some comments
minmax.h: add whitespace around operators and after commas
nilfs2: do not update mtime of renamed directory that is not moved
nilfs2: handle errors that nilfs_prepare_chunk() may return
CREDITS: fix spelling mistake
...
Commit b35108a51c ("jiffies: Define secs_to_jiffies()") introduced
secs_to_jiffies(). As the value here is a multiple of 1000, use
secs_to_jiffies() instead of msecs_to_jiffies to avoid the multiplication.
This is converted using scripts/coccinelle/misc/secs_to_jiffies.cocci with
the following Coccinelle rules:
@@ constant C; @@
- msecs_to_jiffies(C * 1000)
+ secs_to_jiffies(C)
@@ constant C; @@
- msecs_to_jiffies(C * MSEC_PER_SEC)
+ secs_to_jiffies(C)
Link: https://lkml.kernel.org/r/20241210-converge-secs-to-jiffies-v3-6-ddfefd7e9f2a@linux.microsoft.com
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Daniel Mack <daniel@zonque.org>
Cc: David Airlie <airlied@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dick Kennedy <dick.kennedy@broadcom.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Jeff Johnson <jjohnson@kernel.org>
Cc: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jeroen de Borst <jeroendb@google.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Louis Peens <louis.peens@corigine.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Ofir Bitton <obitton@habana.ai>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Praveen Kaligineedi <pkaligineedi@google.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Shailend Chand <shailend@google.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Simon Horman <horms@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Address a bug in the kernel that triggers a "sleeping function called from
invalid context" warning when /sys/kernel/debug/kmemleak is printed under
specific conditions:
- CONFIG_PREEMPT_RT=y
- Set SELinux as the LSM for the system
- Set kptr_restrict to 1
- kmemleak buffer contains at least one item
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 136, name: cat
preempt_count: 1, expected: 0
RCU nest depth: 2, expected: 2
6 locks held by cat/136:
#0: ffff32e64bcbf950 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb8/0xe30
#1: ffffafe6aaa9dea0 (scan_mutex){+.+.}-{3:3}, at: kmemleak_seq_start+0x34/0x128
#3: ffff32e6546b1cd0 (&object->lock){....}-{2:2}, at: kmemleak_seq_show+0x3c/0x1e0
#4: ffffafe6aa8d8560 (rcu_read_lock){....}-{1:2}, at: has_ns_capability_noaudit+0x8/0x1b0
#5: ffffafe6aabbc0f8 (notif_lock){+.+.}-{2:2}, at: avc_compute_av+0xc4/0x3d0
irq event stamp: 136660
hardirqs last enabled at (136659): [<ffffafe6a80fd7a0>] _raw_spin_unlock_irqrestore+0xa8/0xd8
hardirqs last disabled at (136660): [<ffffafe6a80fd85c>] _raw_spin_lock_irqsave+0x8c/0xb0
softirqs last enabled at (0): [<ffffafe6a5d50b28>] copy_process+0x11d8/0x3df8
softirqs last disabled at (0): [<0000000000000000>] 0x0
Preemption disabled at:
[<ffffafe6a6598a4c>] kmemleak_seq_show+0x3c/0x1e0
CPU: 1 UID: 0 PID: 136 Comm: cat Tainted: G E 6.11.0-rt7+ #34
Tainted: [E]=UNSIGNED_MODULE
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0xa0/0x128
show_stack+0x1c/0x30
dump_stack_lvl+0xe8/0x198
dump_stack+0x18/0x20
rt_spin_lock+0x8c/0x1a8
avc_perm_nonode+0xa0/0x150
cred_has_capability.isra.0+0x118/0x218
selinux_capable+0x50/0x80
security_capable+0x7c/0xd0
has_ns_capability_noaudit+0x94/0x1b0
has_capability_noaudit+0x20/0x30
restricted_pointer+0x21c/0x4b0
pointer+0x298/0x760
vsnprintf+0x330/0xf70
seq_printf+0x178/0x218
print_unreferenced+0x1a4/0x2d0
kmemleak_seq_show+0xd0/0x1e0
seq_read_iter+0x354/0xe30
seq_read+0x250/0x378
full_proxy_read+0xd8/0x148
vfs_read+0x190/0x918
ksys_read+0xf0/0x1e0
__arm64_sys_read+0x70/0xa8
invoke_syscall.constprop.0+0xd4/0x1d8
el0_svc+0x50/0x158
el0t_64_sync+0x17c/0x180
%pS and %pK, in the same back trace line, are redundant, and %pS can void
%pK service in certain contexts.
%pS alone already provides the necessary information, and if it cannot
resolve the symbol, it falls back to printing the raw address voiding
the original intent behind the %pK.
Additionally, %pK requires a privilege check CAP_SYSLOG enforced through
the LSM, which can trigger a "sleeping function called from invalid
context" warning under RT_PREEMPT kernels when the check occurs in an
atomic context. This issue may also affect other LSMs.
This change avoids the unnecessary privilege check and resolves the
sleeping function warning without any loss of information.
Link: https://lkml.kernel.org/r/20241217142032.55793-1-acarmina@redhat.com
Fixes: 3a6f33d86b ("mm/kmemleak: use %pK to display kernel pointers in backtrace")
Signed-off-by: Alessandro Carminati <acarmina@redhat.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Clément Léger <clement.leger@bootlin.com>
Cc: Alessandro Carminati <acarmina@redhat.com>
Cc: Eric Chanudet <echanude@redhat.com>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The introduction of iova_depot_pop() in 911aa1245d ("iommu/iova: Make
the rcache depot scale better") confused kmemleak by moving a struct
iova_magazine object from a singly linked list to rcache->depot and
resetting the 'next' pointer referencing it. Unlike doubly linked lists,
the content of the object being referred is never changed on removal from
a singly linked list and the kmemleak checksum heuristics do not detect
such scenario. This leads to false positives like:
unreferenced object 0xffff8881a5301000 (size 1024):
comm "softirq", pid 0, jiffies 4306297099 (age 462.991s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 e7 7d 05 00 00 00 00 00 .........}......
0f b4 05 00 00 00 00 00 b4 96 05 00 00 00 00 00 ................
backtrace:
[<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320
[<ffffffff818a239a>] kmalloc_trace+0x2a/0x60
[<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0
[<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310
[<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0
[<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0
[<ffffffff813ea16b>] __run_timers+0x78b/0xb80
[<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0
[<ffffffff82f1d915>] __do_softirq+0x205/0x8b5
Introduce kmemleak_transient_leak() which resets the object checksum
requiring another scan pass before it is reported (if still unreferenced).
Call this new API in iova_depot_pop().
Link: https://lkml.kernel.org/r/20241104111944.2207155-1-catalin.marinas@arm.com
Link: https://lore.kernel.org/r/ZY1osaGLyT-sdKE8@shredder/
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Ido Schimmel <idosch@idosch.org>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace "corresponding to the give pointer" with "corresponding to the
given pointer"
Link: https://lkml.kernel.org/r/20241010155439.554416-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use IS_ERR_PCPU() instead of IS_ERR() for pointers in the percpu address
space. The patch also fixes following sparse warnings:
kmemleak.c:1063:39: warning: cast removes address space '__percpu' of expression
kmemleak.c:1138:37: warning: cast removes address space '__percpu' of expression
Link: https://lkml.kernel.org/r/20240818210235.33481-2-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "kmemleak: support for percpu memory leak detect'.
This is a rework of this series:
https://lore.kernel.org/lkml/20200921020007.35803-1-chenjun102@huawei.com/
Originally I was investigating a percpu leak on our customer nodes and
having this functionality was a huge help, which lead to this fix [1].
So probably it's a good idea to have it in mainstream too, especially as
after [2] it became much easier to implement (we already have a separate
tree for percpu pointers).
[1] commit 0af8c09c89 ("netfilter: x_tables: fix percpu counter block leak on error path when creating new netns")
[2] commit 39042079a0 ("kmemleak: avoid RCU stalls when freeing metadata for per-CPU pointers")
This patch (of 2):
This basically does:
- Add min_percpu_addr and max_percpu_addr to filter out unrelated data
similar to min_addr and max_addr;
- Set min_count for percpu pointers to 1 to start tracking them;
- Calculate checksum of percpu area as xor of crc32 for each cpu;
- Split pointer lookup and update refs code into separate helper and use
it twice: once as if the pointer is a virtual pointer and once as if
it's percpu.
[ptikhomirov@virtuozzo.com: v2]
Link: https://lkml.kernel.org/r/20240731025526.157529-2-ptikhomirov@virtuozzo.com
Link: https://lkml.kernel.org/r/20240725041223.872472-1-ptikhomirov@virtuozzo.com
Link: https://lkml.kernel.org/r/20240725041223.872472-2-ptikhomirov@virtuozzo.com
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Chen Jun <chenjun102@huawei.com>
Cc: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: fix nested allocation context filtering".
This patchset is the followup to the comment I made earlier today:
https://lore.kernel.org/linux-xfs/ZjAyIWUzDipofHFJ@dread.disaster.area/
Tl;dr: Memory allocations that are done inside the public memory
allocation API need to obey the reclaim recursion constraints placed on
the allocation by the original caller, including the "don't track
recursion for this allocation" case defined by __GFP_NOLOCKDEP.
These nested allocations are generally in debug code that is tracking
something about the allocation (kmemleak, KASAN, etc) and so are
allocating private kernel objects that only that debug system will use.
Neither the page-owner code nor the stack depot code get this right. They
also also clear GFP_ZONEMASK as a separate operation, which is completely
redundant because the constraint filter applied immediately after
guarantees that GFP_ZONEMASK bits are cleared.
kmemleak gets this filtering right. It preserves the allocation
constraints for deadlock prevention and clears all other context flags
whilst also ensuring that the nested allocation will fail quickly,
silently and without depleting emergency kernel reserves if there is no
memory available.
This can be made much more robust, immune to whack-a-mole games and the
code greatly simplified by lifting gfp_kmemleak_mask() to
include/linux/gfp.h and using that everywhere. Also document it so that
there is no excuse for not knowing about it when writing new debug code
that nests allocations.
Tested with lockdep, KASAN + page_owner=on and kmemleak=on over multiple
fstests runs with XFS.
This patch (of 3):
Any "internal" nested allocation done from within an allocation context
needs to obey the high level allocation gfp_mask constraints. This is
necessary for debug code like KASAN, kmemleak, lockdep, etc that allocate
memory for saving stack traces and other information during memory
allocation. If they don't obey things like __GFP_NOLOCKDEP or
__GFP_NOWARN, they produce false positive failure detections.
kmemleak gets this right by using gfp_kmemleak_mask() to pass through the
relevant context flags to the nested allocation to ensure that the
allocation follows the constraints of the caller context.
KASAN recently was foudn to be missing __GFP_NOLOCKDEP due to stack depot
allocations, and even more recently the page owner tracking code was also
found to be missing __GFP_NOLOCKDEP support.
We also don't wan't want KASAN or lockdep to drive the system into OOM
kill territory by exhausting emergency reserves. This is something that
kmemleak also gets right by adding (__GFP_NORETRY | __GFP_NOMEMALLOC |
__GFP_NOWARN) to the allocation mask.
Hence it is clear that we need to define a common nested allocation filter
mask for these sorts of third party nested allocations used in debug code.
So to start this process, lift gfp_kmemleak_mask() to gfp.h and rename it
to gfp_nested_mask(), and convert the kmemleak callers to use it.
Link: https://lkml.kernel.org/r/20240430054604.4169568-1-david@fromorbit.com
Link: https://lkml.kernel.org/r/20240430054604.4169568-2-david@fromorbit.com
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/kmemleak: Minor cleanup & performance tuning".
This series contains 2 simple cleanup patches to slightly reduce memory
and performance overhead.
This patch (of 2):
With commit 56a61617dd ("mm: use stack_depot for recording kmemleak's
backtrace"), the size of kmemleak_object has been reduced by 128 bytes for
64-bit arches. The replacement "depot_stack_handle_t trace_handle" is
actually just 4 bytes long leaving a hole of 4 bytes. By moving up
trace_handle to another existing 4-byte hold, we can save 8 more bytes
from kmemleak_object reducing its overall size from 248 to 240 bytes.
Link: https://lkml.kernel.org/r/20240307190548.963626-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20240307190548.963626-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The system will immediate fill up stack and crash when both
CONFIG_DEBUG_KMEMLEAK and CONFIG_MEM_ALLOC_PROFILING are enabled. Avoid
allocation tagging of kmemleak caches, otherwise recursive allocation
tracking occurs.
Link: https://lkml.kernel.org/r/20240425205516.work.220-kees@kernel.org
Fixes: 279bb991b4d9 ("mm/slab: add allocation accounting into slab allocation and free paths")
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
On systems with large number of CPUs, the following soft lockup splat
might sometimes happen:
[ 2656.001617] watchdog: BUG: soft lockup - CPU#364 stuck for 21s! [ksoftirqd/364:2206]
:
[ 2656.141194] RIP: 0010:_raw_spin_unlock_irqrestore+0x3d/0x70
:
2656.241214] Call Trace:
[ 2656.243971] <IRQ>
[ 2656.246237] ? show_trace_log_lvl+0x1c4/0x2df
[ 2656.251152] ? show_trace_log_lvl+0x1c4/0x2df
[ 2656.256066] ? kmemleak_free_percpu+0x11f/0x1f0
[ 2656.261173] ? watchdog_timer_fn+0x379/0x470
[ 2656.265984] ? __pfx_watchdog_timer_fn+0x10/0x10
[ 2656.271179] ? __hrtimer_run_queues+0x5f3/0xd00
[ 2656.276283] ? __pfx___hrtimer_run_queues+0x10/0x10
[ 2656.281783] ? ktime_get_update_offsets_now+0x95/0x2c0
[ 2656.287573] ? ktime_get_update_offsets_now+0xdd/0x2c0
[ 2656.293380] ? hrtimer_interrupt+0x2e9/0x780
[ 2656.298221] ? __sysvec_apic_timer_interrupt+0x184/0x640
[ 2656.304211] ? sysvec_apic_timer_interrupt+0x8e/0xc0
[ 2656.309807] </IRQ>
[ 2656.312169] <TASK>
[ 2656.326110] kmemleak_free_percpu+0x11f/0x1f0
[ 2656.331015] free_percpu.part.0+0x1b/0xe70
[ 2656.335635] free_vfsmnt+0xb9/0x100
[ 2656.339567] rcu_do_batch+0x3c8/0xe30
[ 2656.363693] rcu_core+0x3de/0x5a0
[ 2656.367433] __do_softirq+0x2d0/0x9a8
[ 2656.381119] run_ksoftirqd+0x36/0x60
[ 2656.385145] smpboot_thread_fn+0x556/0x910
[ 2656.394971] kthread+0x2a4/0x350
[ 2656.402826] ret_from_fork+0x29/0x50
[ 2656.406861] </TASK>
The issue is caused by kmemleak registering each per_cpu_ptr()
corresponding to the __percpu pointer. This is unnecessary since such
individual per-CPU pointers are not tracked anyway. Create a new
object_percpu_tree_root rbtree that stores a single __percpu pointer
together with an OBJECT_PERCPU flag for the kmemleak metadata. Scanning
needs to be done for all per_cpu_ptr() pointers with a cond_resched()
between each CPU iteration to avoid RCU stalls.
[catalin.marinas@arm.com: update comment]
Link: https://lkml.kernel.org/r/20231206114414.2085824-1-catalin.marinas@arm.com
Link: https://lore.kernel.org/r/20231127194153.289626-1-longman@redhat.comLink: https://lkml.kernel.org/r/20231201190829.825856-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Waiman Long <longman@redhat.com>
Closes: https://lore.kernel.org/r/20231127194153.289626-1-longman@redhat.com
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Change /sys/kernel/debug/kmemleak report format slightly, adding
"(extra info)" to the backtrace header:
from: " backtrace:"
to: " backtrace (crc <cksum>):"
The <cksum> allows a user to see recurring backtraces without
detailed/careful reading of multiline stacks. So after cycling
kmemleak-test a few times, I know some leaks are repeating.
bash-5.2# grep backtrace /sys/kernel/debug/kmemleak | wc
62 186 1792
bash-5.2# grep backtrace /sys/kernel/debug/kmemleak | sort -u | wc
37 111 1067
syzkaller parses kmemleak for "unreferenced object" only, so is
unaffected by this change. Other github repos are moribund.
Link: https://lkml.kernel.org/r/20231116224318.124209-3-jim.cromie@gmail.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "tweak kmemleak report format".
These 2 patches make minor changes to the report:
1st strips "age <increasing>" from output. This makes the output
idempotent; unchanging until a new leak is reported.
2nd adds the backtrace.checksum to the "backtrace:" line. This lets a
user see repeats without actually reading the whole backtrace. So now
the backtrace line looks like this:
backtrace (crc 603070071):
I surveyed for un-wanted effects upon users:
Syzkaller parses kmemleak in executor/common_linux.h:
static void check_leaks(char** frames, int nframes)
It just counts occurrences of "unreferenced object", specifically it
does not look for "age", nor would it choke on "crc" being added.
github has 3 repos with "kmemleak" mentioned, all are moribund.
gitlab has 0 hits on "kmemleak".
This patch (of 2):
Displaying age is pretty, but counter-productive; it changes with
current-time, so it surrenders idempotency of the output, which breaks
simple hash-based cataloging of the records by the user.
The trouble: sequential reads, wo new leaks, get new results:
:#> sum /sys/kernel/debug/kmemleak
53439 74 /sys/kernel/debug/kmemleak
:#> sum /sys/kernel/debug/kmemleak
59066 74 /sys/kernel/debug/kmemleak
and age is why (nothing else changes):
:#> grep -v age /sys/kernel/debug/kmemleak | sum
58894 67
:#> grep -v age /sys/kernel/debug/kmemleak | sum
58894 67
Since jiffies is already printed in the "comm" line, age adds nothing.
Notably, syzkaller reads kmemleak only for "unreferenced object", and
won't care about this reform of age-ism. A few moribund github repos
mention it, but don't compile.
Link: https://lkml.kernel.org/r/20231116224318.124209-1-jim.cromie@gmail.com
Link: https://lkml.kernel.org/r/20231116224318.124209-2-jim.cromie@gmail.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
set_track_prepare() will call __alloc_pages() which attempts to acquire
zone->lock(spinlocks), so move it outside object->lock(raw_spinlocks)
because it's not right to acquire spinlocks while holding raw_spinlocks in
RT mode.
Link: https://lkml.kernel.org/r/20231115082138.2649870-3-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fix invalid wait context of set_track_prepare()".
Geert reported an invalid wait context[1] which is resulted by moving
set_track_prepare() inside kmemleak_lock. This is not allowed because in
RT mode, the spinlocks can be preempted but raw_spinlocks can not, so it
is not allowd to acquire spinlocks while holding raw_spinlocks. The
second patch fix same problem in kmemleak_update_trace().
This patch (of 2):
Move the initialisation of object back to__alloc_object() because
set_track_prepare() attempt to acquire zone->lock(spinlocks) while
__link_object is holding kmemleak_lock(raw_spinlocks). This is not right
for RT mode.
This reverts commit 245245c2ff ("mm/kmemleak: move the initialisation
of object to __link_object").
Link: https://lkml.kernel.org/r/20231115082138.2649870-1-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20231115082138.2649870-2-liushixin2@huawei.com
Fixes: 245245c2ff ("mm/kmemleak: move the initialisation of object to __link_object")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Closes: https://lore.kernel.org/linux-mm/CAMuHMdWj0UzwNaxUvcocTfh481qRJpOWwXxsJCTJfu1oCqvgdA@mail.gmail.com/ [1]
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In patch (mm: kmemleak: split __create_object into two functions), the
initialisation of object has been splited in two places. Catalin said it
feels a bit weird and error prone. So leave __alloc_object() to just do
the actual allocation and let __link_object() do the full initialisation.
Link: https://lkml.kernel.org/r/20231023025125.90972-1-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
delete_object_part() can be called by multiple callers in the same time.
If an object is found and removed by a caller, and then another caller try
to find it too, it failed and return directly. It still be recorded by
kmemleak even if it has already been freed to buddy. With DEBUG on,
kmemleak will report the following warning,
kmemleak: Partially freeing unknown object at 0xa1af86000 (size 4096)
CPU: 0 PID: 742 Comm: test_huge Not tainted 6.6.0-rc3kmemleak+ #54
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x37/0x50
kmemleak_free_part_phys+0x50/0x60
hugetlb_vmemmap_optimize+0x172/0x290
? __pfx_vmemmap_remap_pte+0x10/0x10
__prep_new_hugetlb_folio+0xe/0x30
prep_new_hugetlb_folio.isra.0+0xe/0x40
alloc_fresh_hugetlb_folio+0xc3/0xd0
alloc_surplus_hugetlb_folio.constprop.0+0x6e/0xd0
hugetlb_acct_memory.part.0+0xe6/0x2a0
hugetlb_reserve_pages+0x110/0x2c0
hugetlbfs_file_mmap+0x11d/0x1b0
mmap_region+0x248/0x9a0
? hugetlb_get_unmapped_area+0x15c/0x2d0
do_mmap+0x38b/0x580
vm_mmap_pgoff+0xe6/0x190
ksys_mmap_pgoff+0x18a/0x1f0
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Expand __create_object() and move __alloc_object() to the beginning. Then
use kmemleak_lock to protect __find_and_remove_object() and
__link_object() as a whole, which can guarantee all objects are processed
sequentialally.
Link: https://lkml.kernel.org/r/20231018102952.3339837-8-liushixin2@huawei.com
Fixes: 53238a60dd ("kmemleak: Allow partial freeing of memory blocks")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add new __find_and_remove_object() without kmemleak_lock protect, it is in
preparation for the next patch.
Link: https://lkml.kernel.org/r/20231018102952.3339837-7-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The kmemleak object is allocated by mem_pool_alloc(), which could be from
slab or mem_pool[], so it's not suitable using __kmem_cache_free() to free
the object, use __mem_pool_free() instead.
Link: https://lkml.kernel.org/r/20231018102952.3339837-6-liushixin2@huawei.com
Fixes: 0647398a8c ("mm: kmemleak: simple memory allocation pool for kmemleak objects")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
__create_object() consists of two part, the first part allocate a kmemleak
object and initialize it, the second part insert it into object tree.
This function need kmemleak_lock but actually only the second part need
lock.
Split it into two functions, the first function __alloc_object only
allocate a kmemleak object, and the second function __link_object() will
initialize the object and insert it into object tree, use the
kmemleak_lock to protect __link_object() only.
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20231018102952.3339837-5-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With 0x%p, the pointer will be hashed and print (____ptrval____) instead.
And with 0x%pa, the pointer can be successfully printed but with duplicate
prefixes, which looks like:
kmemleak: kmemleak_free(0x(____ptrval____))
kmemleak: kmemleak_free_percpu(0x(____ptrval____))
kmemleak: kmemleak_free_part_phys(0x0x0000000a1af86000)
Use 0x%px instead of 0x%p or 0x%pa to print the pointer. Then the print
will be like:
kmemleak: kmemleak_free(0xffff9111c145b020)
kmemleak: kmemleak_free_percpu(0x00000000000333b0)
kmemleak: kmemleak_free_part_phys(0x0000000a1af80000)
Link: https://lkml.kernel.org/r/20231018102952.3339837-4-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit bde5f6bc68 ("kmemleak: add scheduling point to kmemleak_scan()")
added a cond_resched() call to the struct page scanning loop to prevent
soft lockup from happening. However, soft lockup can still happen in that
loop in some corner cases when the pages that satisfy the "!(pfn & 63)"
check are skipped for some reasons.
Fix this corner case by moving up the cond_resched() check so that it will
be called every 64 pages unconditionally.
Link: https://lkml.kernel.org/r/20230825164947.1317981-1-longman@redhat.com
Fixes: bde5f6bc68 ("kmemleak: add scheduling point to kmemleak_scan()")
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The old name is confusing because it implies the completion of earlier
kmemleak_init(), the new name update to kmemleak_late_initial represents
the completion of kmemleak_late_init().
No functional changes.
Link: https://lkml.kernel.org/r/20230815144128.3623103-3-xiaolei.wang@windriver.com
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/kmemleak: use object_cache instead of
kmemleak_initialized", v3.
Use object_cache instead of kmemleak_initialized to check in
set_track_prepare(), so that memory leaks after kmemleak_init() can be
recorded and Rename kmemleak_initialized to kmemleak_late_initialized
unreferenced object 0xc674ca80 (size 64):
comm "swapper/0", pid 1, jiffies 4294938337 (age 204.880s)
hex dump (first 32 bytes):
80 55 75 c6 80 54 75 c6 00 55 75 c6 80 52 75 c6 .Uu..Tu..Uu..Ru.
00 53 75 c6 00 00 00 00 00 00 00 00 00 00 00 00 .Su..........
This patch (of 2):
kmemleak_initialized is set in kmemleak_late_init(), which also means that
there is no call trace which object's memory leak is before
kmemleak_late_init(), so use object_cache instead of kmemleak_initialized
to check in set_track_prepare() to avoid no call trace records when there
is a memory leak in the code between kmemleak_init() and
kmemleak_late_init().
unreferenced object 0xc674ca80 (size 64):
comm "swapper/0", pid 1, jiffies 4294938337 (age 204.880s)
hex dump (first 32 bytes):
80 55 75 c6 80 54 75 c6 00 55 75 c6 80 52 75 c6 .Uu..Tu..Uu..Ru.
00 53 75 c6 00 00 00 00 00 00 00 00 00 00 00 00 .Su..........
Link: https://lkml.kernel.org/r/20230815144128.3623103-1-xiaolei.wang@windriver.com
Link: https://lkml.kernel.org/r/20230815144128.3623103-2-xiaolei.wang@windriver.com
Fixes: 56a61617dd ("mm: use stack_depot for recording kmemleak's backtrace")
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename stack_depot_want_early_init to stack_depot_request_early_init.
The old name is confusing, as it hints at returning some kind of intention
of stack depot. The new name reflects that this function requests an
action from stack depot instead.
No functional changes.
[akpm@linux-foundation.org: update mm/kmemleak.c]
Link: https://lkml.kernel.org/r/359f31bf67429a06e630b4395816a967214ef753.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 6edda04ccc ("mm/kmemleak: prevent soft lockup in first object
iteration loop of kmemleak_scan()") fixes soft lockup problem in
kmemleak_scan() by periodically doing a cond_resched(). It does take a
reference of the current object before doing it. Unfortunately, if the
object has been deleted from the object_list, the next object pointed to
by its next pointer may no longer be valid after coming back from
cond_resched(). This can result in use-after-free and other nasty
problem.
Fix this problem by adding a del_state flag into kmemleak_object structure
to synchronize the object deletion process between kmemleak_cond_resched()
and __remove_object() to make sure that the object remained in the
object_list in the duration of the cond_resched() call.
Link: https://lkml.kernel.org/r/20230119040111.350923-3-longman@redhat.com
Fixes: 6edda04ccc ("mm/kmemleak: prevent soft lockup in first object iteration loop of kmemleak_scan()")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF", v2.
It was found that a KASAN use-after-free error was reported in the
kmemleak_scan() function. After further examination, it is believe that
even though a reference is taken from the current object, it does not
prevent the object pointed to by the next pointer from going away after a
cond_resched().
To fix that, additional flags are added to make sure that the current
object won't be removed from the object_list during the duration of the
cond_resched() to ensure the validity of the next pointer.
While making the change, I also simplify the current usage of
kmemleak_cond_resched() to make it easier to understand.
This patch (of 2):
The presence of a pinned argument and the 64k loop count make
kmemleak_cond_resched() a bit more complex to read. The pinned argument
is used only by first kmemleak_scan() loop.
Simplify the usage of kmemleak_cond_resched() by removing the pinned
argument and always do a get_object()/put_object() sequence. In addition,
the 64k loop is removed by using need_resched() to decide if
kmemleak_cond_resched() should be called.
Link: https://lkml.kernel.org/r/20230119040111.350923-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20230119040111.350923-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mirsad report the below error which is caused by stack_depot_init()
failure in kvcalloc. Solve this by having stackdepot use
stack_depot_early_init().
On 1/4/23 17:08, Mirsad Goran Todorovac wrote:
I hate to bring bad news again, but there seems to be a problem with the output of /sys/kernel/debug/kmemleak:
[root@pc-mtodorov ~]# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff951c118568b0 (size 16):
comm "kworker/u12:2", pid 56, jiffies 4294893952 (age 4356.548s)
hex dump (first 16 bytes):
6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00 memstick0.......
backtrace:
[root@pc-mtodorov ~]#
Apparently, backtrace of called functions on the stack is no longer
printed with the list of memory leaks. This appeared on Lenovo desktop
10TX000VCR, with AlmaLinux 8.7 and BIOS version M22KT49A (11/10/2022) and
6.2-rc1 and 6.2-rc2 builds. This worked on 6.1 with the same
CONFIG_KMEMLEAK=y and MGLRU enabled on a vanilla mainstream kernel from
Mr. Torvalds' tree. I don't know if this is deliberate feature for some
reason or a bug. Please find attached the config, lshw and kmemleak
output.
[vbabka@suse.cz: remove stack_depot_init() call]
Link: https://lore.kernel.org/all/5272a819-ef74-65ff-be61-4d2d567337de@alu.unizg.hr/
Link: https://lkml.kernel.org/r/1674091345-14799-2-git-send-email-zhaoyang.huang@unisoc.com
Fixes: 56a61617dd ("mm: use stack_depot for recording kmemleak's backtrace")
Reported-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: ke.wang <ke.wang@unisoc.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, %p is used to display kernel pointers in backtrace which result
in a hashed value that is not usable to correlate the address for debug.
Use %pK which will respect the kptr_restrict configuration value and thus
allow to extract meaningful information from the backtrace.
Link: https://lkml.kernel.org/r/20221108094322.73492-1-clement.leger@bootlin.com
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
