Alarm timers utilize hrtimers for normal operation and only switch to the
RTC on suspend. In order to catch already expired timers early and without
going through a timer interrupt cycle, provide a new start function which
internally uses hrtimer_start_range_ns_user().
If hrtimer_start_range_ns_user() detects an already expired timer, it does
not queue it. In that case remove the timer from the alarm base as well.
Return the status queued or not back to the caller to handle the early
expiry.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260408114952.332822525@kernel.org
Switch the arm and rearm callbacks for hrtimer based posix timers over to
hrtimer_start_expires_user() so that already expired timers are not
queued. Hand the result back to the caller, which then queues the signal.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260408114952.266001916@kernel.org
The [re]arm callbacks will return true when the timer was queued and false
if it was already expired at enqueue time.
In both cases the call sites can trivially queue the signal right there,
when the timer was already expired. That avoids a full round trip through
the hrtimer interrupt.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260408114952.198028466@kernel.org
In order to catch expiry times which are already in the past the
timer_arm() and timer_rearm() callbacks need to be able to report back to
the caller whether the timer has been queued or not.
Change the function signature and let all implementations return true for
now. While at it simplify posix_cpu_timer_rearm().
No functional change intended.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260408114952.130222296@kernel.org
Most hrtimer sleepers are user controlled and user space can hand arbitrary
expiry values in as long as they are valid timespecs. If the expiry value
is in the past then this requires a full loop through reprogramming the
clock event device, taking the hrtimer interrupt, waking the task and
reprogram again.
Use hrtimer_start_expires_user() which avoids the full round trip by
checking the timer for expiry on enqueue.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Calvin Owens <calvin@wbinvd.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260408114952.062400833@kernel.org
Calvin reported an odd NMI watchdog lockup which claims that the CPU locked
up in user space. He provided a reproducer, which set's up a timerfd based
timer and then rearms it in a loop with an absolute expiry time of 1ns.
As the expiry time is in the past, the timer ends up as the first expiring
timer in the per CPU hrtimer base and the clockevent device is programmed
with the minimum delta value. If the machine is fast enough, this ends up
in a endless loop of programming the delta value to the minimum value
defined by the clock event device, before the timer interrupt can fire,
which starves the interrupt and consequently triggers the lockup detector
because the hrtimer callback of the lockup mechanism is never invoked.
The clockevents code already has a last resort mechanism to prevent that,
but it's sensible to catch such issues before trying to reprogram the clock
event device.
Provide a variant of hrtimer_start_range_ns(), which sanity checks the
timer after queueing it. It does not so before because the timer might be
armed and therefore needs to be dequeued. also we optimize for the latest
possible point to check, so that the clock event prevention is avoided as
much as possible.
If the timer is already expired _before_ the clock event is reprogrammed,
remove the timer from the queue and signal to the caller that the operation
failed by returning false.
That allows the caller to take immediate action without going through the
loops and hoops of the hrtimer interrupt.
The queueing code can't invoke the timer callback as the caller might hold
a lock which is taken in the callback.
Add a tracepoint which allows to analyze the expired at start situation.
Reported-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Calvin Owens <calvin@wbinvd.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260408114951.995031895@kernel.org
The prevention mechanism against timer interrupt starvation missed to reset
the next_event_forced flag in a couple of places:
- When the clock event state changes. That can cause the flag to be
stale over a shutdown/startup sequence
- When a non-forced event is armed, which then prevents rearming before
that event. If that event is far out in the future this will cause
missed timer interrupts.
- In the suspend wakeup handler.
That led to stalls which have been reported by several people.
Add the missing resets, which fixes the problems for the reporters.
Fixes: d6e152d905 ("clockevents: Prevent timer interrupt starvation")
Reported-by: Hanabishi <i.r.e.c.c.a.k.u.n+kernel.org@gmail.com>
Reported-by: Eric Naim <dnaim@cachyos.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Hanabishi <i.r.e.c.c.a.k.u.n+kernel.org@gmail.com>
Tested-by: Eric Naim <dnaim@cachyos.org>
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/68d1e9ac-2780-4be3-8ee3-0788062dd3a4@gmail.com
Link: https://patch.msgid.link/87340xfeje.ffs@tglx
Everything:
Total patches: 368
Reviews/patch: 1.56
Reviewed rate: 74%
Excluding DAMON:
Total patches: 316
Reviews/patch: 1.77
Reviewed rate: 81%
Excluding DAMON and zram:
Total patches: 306
Reviews/patch: 1.81
Reviewed rate: 82%
Excluding DAMON, zram and maple_tree:
Total patches: 276
Reviews/patch: 2.01
Reviewed rate: 91%
Significant patch series in this merge:
- The 30 patch series "maple_tree: Replace big node with maple copy"
from Liam Howlett is mainly prepararatory work for ongoing development
but it does reduce stack usage and is an improvement.
- The 12 patch series "mm, swap: swap table phase III: remove swap_map"
from Kairui Song offers memory savings by removing the static swap_map.
It also yields some CPU savings and implements several cleanups.
- The 2 patch series "mm: memfd_luo: preserve file seals" from Pratyush
Yadav adds file seal preservation to LUO's memfd code.
- The 2 patch series "mm: zswap: add per-memcg stat for incompressible
pages" from Jiayuan Chen adds additional userspace stats reportng to
zswap.
- The 4 patch series "arch, mm: consolidate empty_zero_page" from Mike
Rapoport implements some cleanups for our handling of ZERO_PAGE() and
zero_pfn.
- The 2 patch series "mm/kmemleak: Improve scan_should_stop()
implementation" from Zhongqiu Han provides an robustness improvement and
some cleanups in the kmemleak code.
- The 4 patch series "Improve khugepaged scan logic" from Vernon Yang
"improves the khugepaged scan logic and reduces CPU consumption by
prioritizing scanning tasks that access memory frequently".
- The 2 patch series "Make KHO Stateless" from Jason Miu simplifies
Kexec Handover by "transitioning KHO from an xarray-based metadata
tracking system with serialization to a radix tree data structure that
can be passed directly to the next kernel"
- The 3 patch series "mm: vmscan: add PID and cgroup ID to vmscan
tracepoints" from Thomas Ballasi and Steven Rostedt enhances vmscan's
tracepointing.
- The 5 patch series "mm: arch/shstk: Common shadow stack mapping helper
and VM_NOHUGEPAGE" from Catalin Marinas is a cleanup for the shadow
stack code: remove per-arch code in favour of a generic implementation.
- The 2 patch series "Fix KASAN support for KHO restored vmalloc
regions" from Pasha Tatashin fixes a WARN() which can be emitted the KHO
restores a vmalloc area.
- The 4 patch series "mm: Remove stray references to pagevec" from Tal
Zussman provides several cleanups, mainly udpating references to "struct
pagevec", which became folio_batch three years ago.
- The 17 patch series "mm: Eliminate fake head pages from vmemmap
optimization" from Kiryl Shutsemau simplifies the HugeTLB vmemmap
optimization (HVO) by changing how tail pages encode their relationship
to the head page.
- The 2 patch series "mm/damon/core: improve DAMOS quota efficiency for
core layer filters" from SeongJae Park improves two problematic
behaviors of DAMOS that makes it less efficient when core layer filters
are used.
- The 3 patch series "mm/damon: strictly respect min_nr_regions" from
SeongJae Park improves DAMON usability by extending the treatment of the
min_nr_regions user-settable parameter.
- The 3 patch series "mm/page_alloc: pcp locking cleanup" from Vlastimil
Babka is a proper fix for a previously hotfixed SMP=n issue. Code
simplifications and cleanups ennsed.
- The 16 patch series "mm: cleanups around unmapping / zapping" from
David Hildenbrand implements "a bunch of cleanups around unmapping and
zapping. Mostly simplifications, code movements, documentation and
renaming of zapping functions".
- The 6 patch series "support batched checking of the young flag for
MGLRU" from Baolin Wang supports batched checking of the young flag for
MGLRU. It's part cleanups; one benchmark shows large performance
benefits for arm64.
- The 5 patch series "memcg: obj stock and slab stat caching cleanups"
from Johannes Weiner provides memcg cleanup and robustness improvements.
- The 5 patch series "Allow order zero pages in page reporting" from
Yuvraj Sakshith enhances page_reporting's free page reporting - it is
presently and undesirably order-0 pages when reporting free memory.
- The 6 patch series "mm: vma flag tweaks" from Lorenzo Stoakes is
cleanup work following from the recent conversion of the VMA flags to a
bitmap.
- The 10 patch series "mm/damon: add optional debugging-purpose sanity
checks" from SeongJae Park adds some more developer-facing debug checks
into DAMON core.
- The 2 patch series "mm/damon: test and document power-of-2
min_region_sz requirement" from SeongJae Park adds an additional DAMON
kunit test and makes some adjustments to the addr_unit parameter
handling.
- The 3 patch series "mm/damon/core: make passed_sample_intervals
comparisons overflow-safe" from SeongJae Park fixes a hard-to-hit time
overflow issue in DAMON core.
- The 7 patch series "mm/damon: improve/fixup/update ratio calculation,
test and documentation" from SeongJae Park is a "batch of misc/minor
improvements and fixups" for DAMON.
- The 4 patch series "mm: move vma_(kernel|mmu)_pagesize() out of
hugetlb.c" from David Hildenbrand fixes a possible issue with dax-device
when CONFIG_HUGETLB=n. Some code movement was required.
- The 6 patch series "zram: recompression cleanups and tweaks" from
Sergey Senozhatsky provides "a somewhat random mix of fixups,
recompression cleanups and improvements" in the zram code.
- The 11 patch series "mm/damon: support multiple goal-based quota
tuning algorithms" from SeongJae Park extend DAMOS quotas goal
auto-tuning to support multiple tuning algorithms that users can select.
- The 4 patch series "mm: thp: reduce unnecessary
start_stop_khugepaged()" from Breno Leitao fixes the khugpaged sysfs
handling so we no longer spam the logs with reams of junk when
starting/stopping khugepaged.
- The 3 patch series "mm: improve map count checks" from Lorenzo Stoakes
provides some cleanups and slight fixes in the mremap, mmap and vma
code.
- The 5 patch series "mm/damon: support addr_unit on default monitoring
targets for modules" from SeongJae Park extends the use of DAMON core's
addr_unit tunable.
- The 5 patch series "mm: khugepaged cleanups and mTHP prerequisites"
from Nico Pache provides cleanups in the khugepaged and is a base for
Nico's planned khugepaged mTHP support.
- The 15 patch series "mm: memory hot(un)plug and SPARSEMEM cleanups"
from David Hildenbrand implements code movement and cleanups in the
memhotplug and sparsemem code.
- The 2 patch series "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and
cleanup CONFIG_MIGRATION" from David Hildenbrand rationalizes some
memhotplug Kconfig support.
- The 6 patch series "change young flag check functions to return bool"
from Baolin Wang is "a cleanup patchset to change all young flag check
functions to return bool".
- The 3 patch series "mm/damon/sysfs: fix memory leak and NULL
dereference issues" from Josh Law and SeongJae Park fixes a few
potential DAMON bugs.
- The 25 patch series "mm/vma: convert vm_flags_t to vma_flags_t in vma
code" from "converts a lot of the existing use of the legacy vm_flags_t
data type to the new vma_flags_t type which replaces it". Mainly in the
vma code.
- The 21 patch series "mm: expand mmap_prepare functionality and usage"
from Lorenzo Stoakes "expands the mmap_prepare functionality, which is
intended to replace the deprecated f_op->mmap hook which has been the
source of bugs and security issues for some time". Cleanups,
documentation, extension of mmap_prepare into filesystem drivers.
- The 13 patch series "mm/huge_memory: refactor zap_huge_pmd()" from
Lorenzo Stoakes simplifies and cleans up zap_huge_pmd(). Additional
cleanups around vm_normal_folio_pmd() and the softleaf functionality are
performed.
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCad3HDQAKCRDdBJ7gKXxA
jrUQAPwNhPk5nPSxnyxjAeQtOBHqgCdnICeEismLajPKd9aYRgEA0s2XAu3tSUYi
GrBnWImHG3s4ePQxVcPCegWTsOUrXgQ=
=1Q7o
-----END PGP SIGNATURE-----
Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "maple_tree: Replace big node with maple copy" (Liam Howlett)
Mainly prepararatory work for ongoing development but it does reduce
stack usage and is an improvement.
- "mm, swap: swap table phase III: remove swap_map" (Kairui Song)
Offers memory savings by removing the static swap_map. It also yields
some CPU savings and implements several cleanups.
- "mm: memfd_luo: preserve file seals" (Pratyush Yadav)
File seal preservation to LUO's memfd code
- "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan
Chen)
Additional userspace stats reportng to zswap
- "arch, mm: consolidate empty_zero_page" (Mike Rapoport)
Some cleanups for our handling of ZERO_PAGE() and zero_pfn
- "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu
Han)
A robustness improvement and some cleanups in the kmemleak code
- "Improve khugepaged scan logic" (Vernon Yang)
Improve khugepaged scan logic and reduce CPU consumption by
prioritizing scanning tasks that access memory frequently
- "Make KHO Stateless" (Jason Miu)
Simplify Kexec Handover by transitioning KHO from an xarray-based
metadata tracking system with serialization to a radix tree data
structure that can be passed directly to the next kernel
- "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas
Ballasi and Steven Rostedt)
Enhance vmscan's tracepointing
- "mm: arch/shstk: Common shadow stack mapping helper and
VM_NOHUGEPAGE" (Catalin Marinas)
Cleanup for the shadow stack code: remove per-arch code in favour of
a generic implementation
- "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin)
Fix a WARN() which can be emitted the KHO restores a vmalloc area
- "mm: Remove stray references to pagevec" (Tal Zussman)
Several cleanups, mainly udpating references to "struct pagevec",
which became folio_batch three years ago
- "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl
Shutsemau)
Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail
pages encode their relationship to the head page
- "mm/damon/core: improve DAMOS quota efficiency for core layer
filters" (SeongJae Park)
Improve two problematic behaviors of DAMOS that makes it less
efficient when core layer filters are used
- "mm/damon: strictly respect min_nr_regions" (SeongJae Park)
Improve DAMON usability by extending the treatment of the
min_nr_regions user-settable parameter
- "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka)
The proper fix for a previously hotfixed SMP=n issue. Code
simplifications and cleanups ensued
- "mm: cleanups around unmapping / zapping" (David Hildenbrand)
A bunch of cleanups around unmapping and zapping. Mostly
simplifications, code movements, documentation and renaming of
zapping functions
- "support batched checking of the young flag for MGLRU" (Baolin Wang)
Batched checking of the young flag for MGLRU. It's part cleanups; one
benchmark shows large performance benefits for arm64
- "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner)
memcg cleanup and robustness improvements
- "Allow order zero pages in page reporting" (Yuvraj Sakshith)
Enhance free page reporting - it is presently and undesirably order-0
pages when reporting free memory.
- "mm: vma flag tweaks" (Lorenzo Stoakes)
Cleanup work following from the recent conversion of the VMA flags to
a bitmap
- "mm/damon: add optional debugging-purpose sanity checks" (SeongJae
Park)
Add some more developer-facing debug checks into DAMON core
- "mm/damon: test and document power-of-2 min_region_sz requirement"
(SeongJae Park)
An additional DAMON kunit test and makes some adjustments to the
addr_unit parameter handling
- "mm/damon/core: make passed_sample_intervals comparisons
overflow-safe" (SeongJae Park)
Fix a hard-to-hit time overflow issue in DAMON core
- "mm/damon: improve/fixup/update ratio calculation, test and
documentation" (SeongJae Park)
A batch of misc/minor improvements and fixups for DAMON
- "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David
Hildenbrand)
Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code
movement was required.
- "zram: recompression cleanups and tweaks" (Sergey Senozhatsky)
A somewhat random mix of fixups, recompression cleanups and
improvements in the zram code
- "mm/damon: support multiple goal-based quota tuning algorithms"
(SeongJae Park)
Extend DAMOS quotas goal auto-tuning to support multiple tuning
algorithms that users can select
- "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao)
Fix the khugpaged sysfs handling so we no longer spam the logs with
reams of junk when starting/stopping khugepaged
- "mm: improve map count checks" (Lorenzo Stoakes)
Provide some cleanups and slight fixes in the mremap, mmap and vma
code
- "mm/damon: support addr_unit on default monitoring targets for
modules" (SeongJae Park)
Extend the use of DAMON core's addr_unit tunable
- "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache)
Cleanups to khugepaged and is a base for Nico's planned khugepaged
mTHP support
- "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand)
Code movement and cleanups in the memhotplug and sparsemem code
- "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup
CONFIG_MIGRATION" (David Hildenbrand)
Rationalize some memhotplug Kconfig support
- "change young flag check functions to return bool" (Baolin Wang)
Cleanups to change all young flag check functions to return bool
- "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh
Law and SeongJae Park)
Fix a few potential DAMON bugs
- "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo
Stoakes)
Convert a lot of the existing use of the legacy vm_flags_t data type
to the new vma_flags_t type which replaces it. Mainly in the vma
code.
- "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes)
Expand the mmap_prepare functionality, which is intended to replace
the deprecated f_op->mmap hook which has been the source of bugs and
security issues for some time. Cleanups, documentation, extension of
mmap_prepare into filesystem drivers
- "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes)
Simplify and clean up zap_huge_pmd(). Additional cleanups around
vm_normal_folio_pmd() and the softleaf functionality are performed.
* tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm: fix deferred split queue races during migration
mm/khugepaged: fix issue with tracking lock
mm/huge_memory: add and use has_deposited_pgtable()
mm/huge_memory: add and use normal_or_softleaf_folio_pmd()
mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio()
mm/huge_memory: separate out the folio part of zap_huge_pmd()
mm/huge_memory: use mm instead of tlb->mm
mm/huge_memory: remove unnecessary sanity checks
mm/huge_memory: deduplicate zap deposited table call
mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE()
mm/huge_memory: add a common exit path to zap_huge_pmd()
mm/huge_memory: handle buggy PMD entry in zap_huge_pmd()
mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc
mm/huge: avoid big else branch in zap_huge_pmd()
mm/huge_memory: simplify vma_is_specal_huge()
mm: on remap assert that input range within the proposed VMA
mm: add mmap_action_map_kernel_pages[_full]()
uio: replace deprecated mmap hook with mmap_prepare in uio_info
drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare
mm: allow handling of stacked mmap_prepare hooks in more drivers
...
- Make the handling of compat functions consistent and more robust
- Rework the underlying data store so that it is dynamically
allocated, which allows the conversion of the last holdout SPARC64
to the generic VDSO implementation
- Rework the SPARC64 VDSO to utilize the generic implementation
- Mop up the left overs of the non-generic VDSO support in the core
code.
- Expand the VDSO selftest and make them more robust
- Allow time namespaces to be enabled independently of the generic
VDSO support, which was not possible before due to SPARC64 not
using it.
- Various cleanups and improvements in the related code.
-----BEGIN PGP SIGNATURE-----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=8ixX
-----END PGP SIGNATURE-----
Merge tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull vdso updates from Thomas Gleixner:
- Make the handling of compat functions consistent and more robust
- Rework the underlying data store so that it is dynamically allocated,
which allows the conversion of the last holdout SPARC64 to the
generic VDSO implementation
- Rework the SPARC64 VDSO to utilize the generic implementation
- Mop up the left overs of the non-generic VDSO support in the core
code
- Expand the VDSO selftest and make them more robust
- Allow time namespaces to be enabled independently of the generic VDSO
support, which was not possible before due to SPARC64 not using it
- Various cleanups and improvements in the related code
* tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
timens: Use task_lock guard in timens_get*()
timens: Use mutex guard in proc_timens_set_offset()
timens: Simplify some calls to put_time_ns()
timens: Add a __free() wrapper for put_time_ns()
timens: Remove dependency on the vDSO
vdso/timens: Move functions to new file
selftests: vDSO: vdso_test_correctness: Add a test for time()
selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c
selftests: vDSO: vdso_test_correctness: Handle different tv_usec types
selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks
selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks
Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers"
random: vDSO: Remove ifdeffery
random: vDSO: Trim vDSO includes
vdso/datapage: Trim down unnecessary includes
vdso/datapage: Remove inclusion of gettimeofday.h
vdso/helpers: Explicitly include vdso/processor.h
vdso/gettimeofday: Add explicit includes
random: vDSO: Add explicit includes
MIPS: vdso: Explicitly include asm/vdso/vdso.h
...
Calvin reported an odd NMI watchdog lockup which claims that the CPU locked
up in user space. He provided a reproducer, which sets up a timerfd based
timer and then rearms it in a loop with an absolute expiry time of 1ns.
As the expiry time is in the past, the timer ends up as the first expiring
timer in the per CPU hrtimer base and the clockevent device is programmed
with the minimum delta value. If the machine is fast enough, this ends up
in a endless loop of programming the delta value to the minimum value
defined by the clock event device, before the timer interrupt can fire,
which starves the interrupt and consequently triggers the lockup detector
because the hrtimer callback of the lockup mechanism is never invoked.
As a first step to prevent this, avoid reprogramming the clock event device
when:
- a forced minimum delta event is pending
- the new expiry delta is less then or equal to the minimum delta
Thanks to Calvin for providing the reproducer and to Borislav for testing
and providing data from his Zen5 machine.
The problem is not limited to Zen5, but depending on the underlying
clock event device (e.g. TSC deadline timer on Intel) and the CPU speed
not necessarily observable.
This change serves only as the last resort and further changes will be made
to prevent this scenario earlier in the call chain as far as possible.
[ tglx: Updated to restore the old behaviour vs. !force and delta <= 0 and
fixed up the tick-broadcast handlers as pointed out by Borislav ]
Fixes: d316c57ff6 ("[PATCH] clockevents: add core functionality")
Reported-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Calvin Owens <calvin@wbinvd.org>
Tested-by: Borislav Petkov <bp@alien8.de>
Link: https://lore.kernel.org/lkml/acMe-QZUel-bBYUh@mozart.vkv.me/
Link: https://patch.msgid.link/20260407083247.562657657@kernel.org
In alarmtimer_suspend(), timerqueue_getnext() is called under
base->lock, but next->expires is read after the lock is released.
This is safe because suspend freezes all relevant task contexts,
but reading the node while holding the lock makes the code easier
to reason about and not worry about a theoretical UAF.
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260407143627.19405-1-zhanxusheng@xiaomi.com
Commit 56534673ce ("tick/nohz: Optimize check_tick_dependency() with
early return") added a fast path that returns !val when the tick_stop
tracepoint is disabled.
This is inverted: the slow path returns true when a dependency IS found
(val != 0), but !val returns true when val is zero (no dependency). The
result is that can_stop_full_tick() sees "dependency found" when there are
none, and the tick never stops on nohz_full CPUs.
Fix this by returning !!val instead of !val, matching the slow-path semantics.
Fixes: 56534673ce ("tick/nohz: Optimize check_tick_dependency() with early return")
Signed-off-by: Josh Snyder <josh@code406.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: Claude:claude-opus-4-6
Link: https://patch.msgid.link/20260402-fix-idle-tick2-v1-1-eecb589649d3@code406.com
The #endif comment says "BITS_PER_LONG >= 64", but the corresponding #if
guard is "BITS_PER_LONG < 64".
The comment was originally correct when the block had a three-way
#if/#else/#endif structure, where the #else branch provided a 64-bit inline
version. Commit 79bf2bb335 ("[PATCH] tick-management: dyntick / highres
functionality") removed the #else branch but did not update the #endif
comment, leaving it inconsistent with the remaining #if condition.
Fix the comment to match the preprocessor guard.
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260331074811.26147-1-zhanxusheng@xiaomi.com
The comment in exit_itimers() still refers to itimer_delete(),
which was replaced by posix_timer_delete(). Update the comment
accordingly.
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260326142210.98632-1-zhanxusheng@xiaomi.com
Previously, missing time namespace support in the vDSO meant that time
namespaces needed to be disabled globally. This was expressed in a hard
dependency on the generic vDSO library. This also meant that architectures
without any vDSO or only a stub vDSO could not enable time namespaces.
Now that all architectures using a real vDSO are using the generic library,
that dependency is not necessary anymore.
Remove the dependency and let all architectures enable time namespaces.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260326-vdso-timens-decoupling-v2-2-c82693a7775f@linutronix.de
As a preparation of the untangling of time namespaces and the vDSO, move
the glue functions between those subsystems into a new file.
While at it, switch the mutex lock and mmap_read_lock() in the vDSO
namespace code to guard().
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260326-vdso-timens-decoupling-v2-1-c82693a7775f@linutronix.de
Calling smp_processor_id() on:
- In CONFIG_DEBUG_PREEMPT=y, if preemption/irq is disabled, then it does
not print any warning.
- In CONFIG_DEBUG_PREEMPT=n, it doesn't do anything apart from getting
__smp_processor_id
So with both CONFIG_DEBUG_PREEMPT=y/n, in preemption disabled section it is
better to cache the value. It saves a few cycles. Though tiny, repeated
adds up.
timer_clear_idle() is called with interrupts disabled. So cache the value
once.
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Link: https://patch.msgid.link/20260323193630.640311-5-sshegde@linux.ibm.com
alarm_timer_forward() passes arguments to alarm_forward() in the wrong
order:
alarm_forward(alarm, timr->it_interval, now);
However, alarm_forward() is defined as:
u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);
and uses the second argument as the current time:
delta = ktime_sub(now, alarm->node.expires);
Passing the interval as "now" results in incorrect delta computation,
which can lead to missed expirations or incorrect overrun accounting.
This issue has been present since the introduction of
alarm_timer_forward().
Fix this by swapping the arguments.
Fixes: e7561f1633 ("alarmtimer: Implement forward callback")
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260323061130.29991-1-zhanxusheng@xiaomi.com
-----BEGIN PGP SIGNATURE-----
iQFSBAABCgA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmm3G/UeHHRvcnZhbGRz
QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGZJUH/R0vQ3Vha48QDEic
1NREwaHxAoTFi0i3y7OPPklqrP2V09D1qg4Q6fExYQVTQgV6F2DRjVbyPKrmr4ay
BA6aHrUdnFngYHpDlI1b1r7rJiAIN4WFHl7StO70bS+EB+UPsP9cfP3CKXUfKfqT
kyHXzUrd5QnjYmlb9rQw1E6rzsRamNtGUtZf7TwDidJYjtm3sPeDHUkjyRy4xkYd
UouIu6W7UXoicl38bJAgaWBY5BiYtjN6ktnY4/gcqDeqYd7mTM3Eb1B+OSXgFfip
F0OYfJhfWn+63WnPA+1I5jXWC1UrdVXTMK/NTYjhmGlfdmkLcWDlNGtu+qKZbpwj
fmF3Kyo=
=6nX1
-----END PGP SIGNATURE-----
Merge tag 'v7.0-rc4' into timers/core, to resolve conflict
Resolve conflict between this change in the upstream kernel:
4c652a4772 ("rseq: Mark rseq_arm_slice_extension_timer() __always_inline")
... and this pending change in timers/core:
0e98eb1481 ("entry: Prepare for deferred hrtimer rearming")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The clocksource watchdog code has over time reached the state of an
impenetrable maze of duct tape and staples. The original design, which was
made in the context of systems far smaller than today, is based on the
assumption that the to be monitored clocksource (TSC) can be trivially
compared against a known to be stable clocksource (HPET/ACPI-PM timer).
Over the years it turned out that this approach has major flaws:
- Long delays between watchdog invocations can result in wrap arounds
of the reference clocksource
- Scalability of the reference clocksource readout can degrade on large
multi-socket systems due to interconnect congestion
This was addressed with various heuristics which degraded the accuracy of
the watchdog to the point that it fails to detect actual TSC problems on
older hardware which exposes slow inter CPU drifts due to firmware
manipulating the TSC to hide SMI time.
To address this and bring back sanity to the watchdog, rewrite the code
completely with a different approach:
1) Restrict the validation against a reference clocksource to the boot
CPU, which is usually the CPU/Socket closest to the legacy block which
contains the reference source (HPET/ACPI-PM timer). Validate that the
reference readout is within a bound latency so that the actual
comparison against the TSC stays within 500ppm as long as the clocks
are stable.
2) Compare the TSCs of the other CPUs in a round robin fashion against
the boot CPU in the same way the TSC synchronization on CPU hotplug
works. This still can suffer from delayed reaction of the remote CPU
to the SMP function call and the latency of the control variable cache
line. But this latency is not affecting correctness. It only affects
the accuracy. With low contention the readout latency is in the low
nanoseconds range, which detects even slight skews between CPUs. Under
high contention this becomes obviously less accurate, but still
detects slow skews reliably as it solely relies on subsequent readouts
being monotonically increasing. It just can take slightly longer to
detect the issue.
3) Rewrite the watchdog test so it tests the various mechanisms one by
one and validating the result against the expectation.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Daniel J Blueman <daniel@quora.org>
Reviewed-by: Jiri Wiesner <jwiesner@suse.de>
Reviewed-by: Daniel J Blueman <daniel@quora.org>
Link: https://patch.msgid.link/20260123231521.926490888@kernel.org
Link: https://patch.msgid.link/87h5qeomm5.ffs@tglx
Using a non-continuous aka untrusted clocksource as a watchdog for another
untrusted clocksource is equivalent to putting the fox in charge of the
henhouse.
That's especially true with the jiffies clocksource which depends on
interrupt delivery based on a periodic timer. Neither the frequency of that
timer is trustworthy nor the kernel's ability to react on it in a timely
manner and rearm it if it is not self rearming.
Just don't bother to deal with this. It's not worth the trouble and only
relevant to museum piece hardware.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260123231521.858743259@kernel.org
The container_of() call is open-coded multiple times.
Add a helper macro.
Use container_of_const() to preserve constness.
Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-12-095357392669@linutronix.de
This pointer indirection is a remnant from when ktime_t was a struct,
today it is pointless.
Drop the pointer indirection.
Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-9-095357392669@linutronix.de
The value will be assigned to before any usage.
No other function in hrtimer.c does such a zero-initialization.
Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-7-095357392669@linutronix.de
Neither the array nor the offsets it is pointing to are meant to be
changed through the array.
Mark both the array and the values it points to as const.
Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-5-095357392669@linutronix.de
In aux_clock_enable() the clocksource from tkr_raw is used to call
tk_setup_internals(). Do the same in tk_aux_update_clocksource(). While
the clocksources will be the same in any case, this is less confusing.
Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-4-095357392669@linutronix.de
When the hrtimer_interrupt needs to restart more than 3 times and still has
expired timers, the interrupt is considered hung. To give the system a
little time to recover, the hardware timer is programmed a little into the
future.
Prior to commit 2889243848 ("hrtimer: Re-arrange hrtimer_interrupt()"),
this was relative to the amount of time spend serving the interrupt with a
max of 100 msec.
However, in order to simplify, and because this condition 'should' not
happen, the timeout was unconditionally set to 100 msec.
'Obviously' there is a benchmark that hits this hard, by programming a
ton of very short timers :-/
Since reprogramming is decoupled from the interrupt handling, the actual
execution time is lost, however the code does track max_hang_time. Using
that, rather than the 100 ms max restores performance.
stress-ng --timeout 60 --times --verify --metrics --no-rand-seed --timermix 64
bogo ops/s
288924384856^1: 23715979.93
288924384856: 11550049.77
patched: 23361116.78
Additionally, Thomas noted that cpu_base->hang_detected should not be
cleared until the next interrupt, such that __hrtimer_reprogram() won't
undo the extra delay.
Fixes: 2889243848 ("hrtimer: Re-arrange hrtimer_interrupt()")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260311121500.GF652779@noisy.programming.kicks-ass.net
Closes: https://lore.kernel.org/oe-lkp/202603102229.74b9dee4-lkp@intel.com
The trace_clock_jiffies() function that handles the "uptime" clock for
tracing calls jiffies_64_to_clock_t(). This causes the function tracer to
constantly recurse when the tracing clock is set to "uptime". Mark it
notrace to prevent unnecessary recursion when using the "uptime" clock.
Fixes: 58d4e21e50 ("tracing: Fix wraparound problems in "uptime" trace clock")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260306212403.72270bb2@robin
After sparc64, there are no remaining users of ARCH_CLOCKSOURCE_DATA
and it can just be removed.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260304-vdso-sparc64-generic-2-v6-14-d8eb3b0e1410@linutronix.de
[Thomas: drop sparc64 bits from the patch]
permissive for auxiliary clocks, to not reject syscalls
based on the status field that do not try to modify the
status field. This makes ABI behavior in clock_adjtime()
consistent with CLOCK_REALTIME.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----
iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmmsxzkRHG1pbmdvQGtl
cm5lbC5vcmcACgkQEnMQ0APhK1hq8g//fRTp9p2pVfmRWUoxWELrT/bMK1r+D6F3
6BYkwp68peRhchVrFxkI/Y37rjAIC8CXZSPuvkubqIROrH3gA7SCCQYCcZKdss+t
i3lbpQF8IbagPIS5btpOAN2KRCu2S7aqjDdH0rWb9VhQdlW7fI71Z72Uz07YEA+q
TWpy3gE531P/dgAqcvIAyMHnFZDCb1S6z8wZvT3SV4r4GkczfXpTFyNHHtETSu0V
7isuOBfloM4HpDU50oUotlqBiwigH27J2Ad6aIrnCA7iaQPrzREysG+8E96ShhaB
g6+qaQS5gTgFryA1bggA6LzGveLOI8bjy2kZ2SnZWuFPj46OReGIuwK4kyY07jz2
xk0sd37alN16ETKhGVLfAgjmzVGoKVNnp4ak9J3VmMbxWEmXeObuOC8SmF9VImc1
4bRaG9+Tlfd4DtOOz2+E4VcPE1D9A2tMw4esgUaXRrrp4GlEcKOJ5PRlWj0uGvrh
xLPLbL0XIiWsjMsHdVs4Gq9Z0MvfRHc4VLOviIqLFtHox2DscZypPkyjKAv5inp0
/VWyUYJkkr07RMQQ3nqHnP+lzAfO2aSeZ72D9NnHStL3RPbGC4jYvpoi8dnH0/TT
PKJgj2jb7u3h+1cxKBi1RM0JbxUYD5+4N8zfJISa9uqkHZ3XY3VyuuT+2RHO6CQp
d1BdX0V4oDA=
=zjov
-----END PGP SIGNATURE-----
Merge tag 'timers-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Ingo Molnar:
"Make clock_adjtime() syscall timex validation slightly more permissive
for auxiliary clocks, to not reject syscalls based on the status field
that do not try to modify the status field.
This makes the ABI behavior in clock_adjtime() consistent with
CLOCK_REALTIME"
* tag 'timers-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix timex status validation for auxiliary clocks
Borislav reported a division by zero in the timekeeping code and random
hangs with the new coupled clocksource/clockevent functionality.
It turned out that the TSC clocksource is not always updating the
freq_khz field of the clocksource on registration. The coupled mode
conversion calculation requires the frequency and as it's not
initialized the resulting factor is zero or a random value. As a
consequence this causes a division by zero or random boot hangs.
Instead of chasing down all clocksources which fail to update that
member, fill it in at registration time where the caller has to supply
the frequency anyway. Except for special clocksources like jiffies which
never can have coupled mode.
To make this more robust put a check into the registration function to
validate that the caller supplied a frequency if the coupled mode
feature bit is set. If not, emit a warning and clear the feature bit.
Fixes: cd38bdb8e6 ("timekeeping: Provide infrastructure for coupled clockevents")
Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/87cy1jsa4m.ffs@tglx
Closes: https://lore.kernel.org/20260303213027.GA2168957@ax162
Nathan reported a boot failure after the coupled clocksource/event support
was enabled for the TSC deadline timer. It turns out that on the affected
test systems the TSC frequency is not refined against HPET, so it is
registered with the same frequency as the TSC-early clocksource.
As a consequence the update function which checks for a change of the
shift/mult pair of the clocksource fails to compute the conversion
limit, which is zero initialized. This check is there to avoid pointless
computations on every timekeeping update cycle (tick).
So the actual clockevent conversion function limits the delta expiry to
zero, which means the timer is always programmed to expire in the
past. This obviously results in a spectacular timer interrupt storm,
which goes unnoticed because the per CPU interrupts on x86 are not
exposed to the runaway detection mechanism and the NMI watchdog is not
yet functional. So the machine simply stops booting.
That did not show up in testing. All test machines refine the TSC frequency
so TSC has a differrent shift/mult pair than TSC-early and the conversion
limit is properly initialized.
Cure that by setting the conversion limit right at the point where the new
clocksource is installed.
Fixes: cd38bdb8e6 ("timekeeping: Provide infrastructure for coupled clockevents")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/87bjh4zies.ffs@tglx
Closes: https://lore.kernel.org/20260303012905.GA978396@ax162
The timekeeping_validate_timex() function validates the timex status
of an auxiliary system clock even when the status is not to be changed,
which causes unexpected errors for applications that make read-only
clock_adjtime() calls, or set some other timex fields, but without
clearing the status field.
Do the AUX-specific status validation only when the modes field contains
ADJ_STATUS, i.e. the application is actually trying to change the
status. This makes the AUX-specific clock_adjtime() behavior consistent
with CLOCK_REALTIME.
Fixes: 4eca49d0b6 ("timekeeping: Prepare do_adtimex() for auxiliary clocks")
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260225085231.276751-1-mlichvar@redhat.com
* Fix error when reporting jiffies converted values back to user space
Return the converted value instead of "Invalid argument" error.
* Testing
Spent around a week in linux-next -enough for this small fix-
-----BEGIN PGP SIGNATURE-----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=F0SK
-----END PGP SIGNATURE-----
Merge tag 'sysctl-7.00-fixes-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl fix from Joel Granados:
- Fix error when reporting jiffies converted values back to user space
Return the converted value instead of "Invalid argument" error
* tag 'sysctl-7.00-fixes-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
time/jiffies: Fix sysctl file error on configurations where USER_HZ < HZ
Commit 2dc164a48e ("sysctl: Create converter functions with two new
macros") incorrectly returns error to user space when jiffies sysctl
converter is used. The old overflow check got replaced with an
unconditional one:
+ if (USER_HZ < HZ)
+ return -EINVAL;
which will always be true on configurations with "USER_HZ < HZ".
Remove the check; it is no longer needed as clock_t_to_jiffies() returns
ULONG_MAX for the overflow case and proc_int_u2k_conv_uop() checks for
"> INT_MAX" after conversion
Fixes: 2dc164a48e ("sysctl: Create converter functions with two new macros")
Reported-by: Colm Harrington <colm.harrington@oracle.com>
Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
- Fix circular locking dependency in cpuset partition code by deferring
housekeeping_update() calls to a workqueue instead of calling them
directly under cpus_read_lock.
- Fix null-ptr-deref in rebuild_sched_domains_cpuslocked() when
generate_sched_domains() returns NULL due to kmalloc failure.
- Fix incorrect cpuset behavior for effective_xcpus in
partition_xcpus_del() and cpuset_update_tasks_cpumask() in
update_cpumasks_hier().
- Fix race between task migration and cgroup iteration.
-----BEGIN PGP SIGNATURE-----
iIQEABYKACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCaadVVQ4cdGpAa2VybmVs
Lm9yZwAKCRCxYfJx3gVYGef0AQDLuJE3vzc2VeCBc4rGcj7ZSRmc3tc28lOqHRzi
XEx1iwD+PeFcb9wt1CTqA5hAiIY1LGR/5iO1kTH7paRd16DBRAc=
=S8WE
-----END PGP SIGNATURE-----
Merge tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Fix circular locking dependency in cpuset partition code by
deferring housekeeping_update() calls to a workqueue instead
of calling them directly under cpus_read_lock
- Fix null-ptr-deref in rebuild_sched_domains_cpuslocked() when
generate_sched_domains() returns NULL due to kmalloc failure
- Fix incorrect cpuset behavior for effective_xcpus in
partition_xcpus_del() and cpuset_update_tasks_cpumask()
in update_cpumasks_hier()
- Fix race between task migration and cgroup iteration
* tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/cpuset: fix null-ptr-deref in rebuild_sched_domains_cpuslocked
cgroup/cpuset: Call housekeeping_update() without holding cpus_read_lock
cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue
cgroup/cpuset: Move housekeeping_update()/rebuild_sched_domains() together
kselftest/cgroup: Simplify test_cpuset_prs.sh by removing "S+" command
cgroup/cpuset: Set isolated_cpus_updating only if isolated_cpus is changed
cgroup/cpuset: Clarify exclusion rules for cpuset internal variables
cgroup/cpuset: Fix incorrect use of cpuset_update_tasks_cpumask() in update_cpumasks_hier()
cgroup/cpuset: Fix incorrect change to effective_xcpus in partition_xcpus_del()
cgroup: fix race between task migration and iteration
for the common HZ=100, 250 or 1000 cases, only inlining them
for odd HZ values like HZ=300.
The inlining overhead showed up in performance tests of the TCP code.
(Marked as an RFC pull request, as it's not a regression.)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=duTI
-----END PGP SIGNATURE-----
Merge tag 'timers-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Ingo Molnar:
"Improve the inlining of jiffies_to_msecs() and jiffies_to_usecs(), for
the common HZ=100, 250 or 1000 cases. Only use a function call for odd
HZ values like HZ=300 that generate more code.
The function call overhead showed up in performance tests of the TCP
code"
* tag 'timers-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/jiffies: Inline jiffies_to_msecs() and jiffies_to_usecs()
When modifying the expiry of a armed timer it is first dequeued, then the
expiry value is updated and then it is queued again.
This can be avoided when the new expiry value is within the range of the
previous and the next timer as that does not change the position in the RB
tree.
The linked timerqueue allows to peak ahead to the neighbours and check
whether the new expiry time is within the range of the previous and next
timer. If so just modify the timer in place and spare the enqueue and
requeue effort, which might end up rotating the RB tree twice for nothing.
This speeds up the handling of frequently rearmed hrtimers, like the hrtick
scheduler timer significantly.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.873359816@kernel.org
To prepare for optimizing the rearming of enqueued timers, switch to the
linked timerqueue. That allows to check whether the new expiry time changes
the position of the timer in the RB tree or not, by checking the new expiry
time against the previous and the next timers expiry.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.806643179@kernel.org
Replace the open coded container_of() orgy with a trivial
clock_base_next_timer() helper.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.532927977@kernel.org
The per clock base cached expiry time allows to do a more efficient
evaluation of the next expiry on a CPU.
Separate the reprogramming evaluation from the NOHZ idle evaluation which
needs to exclude the NOHZ timer to keep the reprogramming path lean and
clean.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.468186893@kernel.org
Evaluating the next expiry time of all clock bases is cache line expensive
as the expiry time of the first expiring timer is not cached in the base
and requires to access the timer itself, which is definitely in a different
cache line.
It's way more efficient to keep track of the expiry time on enqueue and
dequeue operations as the relevant data is already in the cache at that
point.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.404839710@kernel.org
Most times there is no change between hrtimer_interrupt() deferring the rearm
and the invocation of hrtimer_rearm_deferred(). In those cases it's a pointless
exercise to re-evaluate the next expiring timer.
Cache the required data and use it if nothing changed.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.338569372@kernel.org
Currently hrtimer_interrupt() runs expired timers, which can re-arm
themselves, after which it computes the next expiration time and
re-programs the hardware.
However, things like HRTICK, a highres timer driving preemption, cannot
re-arm itself at the point of running, since the next task has not been
determined yet. The schedule() in the interrupt return path will switch to
the next task, which then causes a new hrtimer to be programmed.
This then results in reprogramming the hardware at least twice, once after
running the timers, and once upon selecting the new task.
Notably, *both* events happen in the interrupt.
By pushing the hrtimer reprogram all the way into the interrupt return
path, it runs after schedule() picks the new task and the double reprogram
can be avoided.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.273488269@kernel.org
The hrtimer interrupt expires timers and at the end of the interrupt it
rearms the clockevent device for the next expiring timer.
That's obviously correct, but in the case that a expired timer set
NEED_RESCHED the return from interrupt ends up in schedule(). If HRTICK is
enabled then schedule() will modify the hrtick timer, which causes another
reprogramming of the hardware.
That can be avoided by deferring the rearming to the return from interrupt
path and if the return results in a immediate schedule() invocation then it
can be deferred until the end of schedule().
To make this correct the affected code parts need to be made aware of this.
Provide empty stubs for the deferred rearming mechanism, so that the
relevant code changes for entry, softirq and scheduler can be split up into
separate changes independent of the actual enablement in the hrtimer code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163431.000891171@kernel.org
The upcoming deferred rearming scheme has the same effect as the deferred
rearming when the hrtimer interrupt is executing. So it can reuse the
in_hrtirq flag, but when it gets deferred beyond the hrtimer interrupt
path, then the name does not make sense anymore.
Rename it to deferred_rearm upfront to keep the actual functional change
separate from the mechanical rename churn.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.935623347@kernel.org
Rework hrtimer_interrupt() such that reprogramming is split out into an
independent function at the end of the interrupt.
This prepares for reprogramming getting delayed beyond the end of
hrtimer_interrupt().
Notably, this changes the hang handling to always wait 100ms instead of
trying to keep it proportional to the actual delay. This simplifies the
state, also this really shouldn't be happening.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.870639266@kernel.org
As the base switch can be avoided completely when the base stays the same
the remove/enqueue handling can be more streamlined.
Split it out into a separate function which handles both in one go which is
way more efficient and makes the code simpler to follow.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.737600486@kernel.org
The decision to keep a timer which is associated to the local CPU on that
CPU does not take NOHZ information into account. As a result there are a
lot of hrtimer base switch invocations which end up not switching the base
and stay on the local CPU. That's just work for nothing and can be further
improved.
If the local CPU is part of the NOISE housekeeping mask, then check:
1) Whether the local CPU has the tick running, which means it is
either not idle or already expecting a timer soon.
2) Whether the tick is stopped and need_resched() is set, which
means the CPU is about to exit idle.
This reduces the amount of hrtimer base switch attempts, which end up on
the local CPU anyway, significantly and prepares for further optimizations.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.673473029@kernel.org
The decision whether to keep timers on the local CPU or on the CPU they are
associated to is suboptimal and causes the expensive switch_hrtimer_base()
mechanism to be invoked more than necessary. This is especially true for
pinned timers.
Rewrite the decision logic so that the current base is kept if:
1) The callback is running on the base
2) The timer is associated to the local CPU and the first expiring timer as
that allows to optimize for reprogramming avoidance
3) The timer is associated to the local CPU and pinned
4) The timer is associated to the local CPU and timer migration is
disabled.
Only #2 was covered by the original code, but especially #3 makes a
difference for high frequency rearming timers like the scheduler hrtick
timer. If timer migration is disabled, then #4 avoids most of the base
switches.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.607935269@kernel.org
All 'u8' flags are true booleans, so make it entirely clear that these can
only contain true or false.
This is especially true for hrtimer::state, which has a historical leftover
of using the state with bitwise operations. That was used in the early
hrtimer implementation with several bits, but then converted to a boolean
state. But that conversion missed to replace the bit OR and bit check
operations all over the place, which creates suboptimal code. As of today
'state' is a misnomer because it's only purpose is to reflect whether the
timer is enqueued into the RB-tree or not. Rename it to 'is_queued' and
make all operations on it boolean.
This reduces text size from 8926 to 8732 bytes.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.542427240@kernel.org
Use bool for the various flags as that creates better code in the hot path.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.475262618@kernel.org
As this code has some major surgery ahead, clean up coding style and bring
comments up to date.
No functional change intended.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.342740952@kernel.org
hrtimer_start() when invoked with an already armed timer traces like:
<comm>-.. [032] d.h2. 5.002263: hrtimer_cancel: hrtimer= ....
<comm>-.. [032] d.h1. 5.002263: hrtimer_start: hrtimer= ....
Which is incorrect as the timer doesn't get canceled. Just the expiry time
changes. The internal dequeue operation which is required for that is not
really interesting for trace analysis. But it makes it tedious to keep real
cancellations and the above case apart.
Remove the cancel tracing in hrtimer_start() and add a 'was_armed'
indicator to the hrtimer start tracepoint, which clearly indicates what the
state of the hrtimer is when hrtimer_start() is invoked:
<comm>-.. [032] d.h1. 6.200103: hrtimer_start: hrtimer= .... was_armed=0
<comm>-.. [032] d.h1. 6.200558: hrtimer_start: hrtimer= .... was_armed=1
Fixes: c6a2a17702 ("hrtimer: Add tracepoint for hrtimers")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.208491877@kernel.org
The debug object coverage in hrtimer_start_range_ns() happens too late to
do anything useful. Implement the init assert assertion part and invoke
that early in hrtimer_start_range_ns().
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.143098153@kernel.org
Some clockevent devices are coupled to the system clocksource by
implementing a less than or equal comparator which compares the programmed
absolute expiry time against the underlying time counter.
The timekeeping core provides a function to convert and absolute
CLOCK_MONOTONIC based expiry time to a absolute clock cycles time which can
be directly fed into the comparator. That spares two time reads in the next
event progamming path, one to convert the absolute nanoseconds time to a
delta value and the other to convert the delta value back to a absolute
time value suitable for the comparator.
Provide a new clocksource callback which takes the absolute cycle value and
wire it up in clockevents_program_event(). Similar to clocksources allow
architectures to inline the rearm operation.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.010425428@kernel.org
Some architectures have clockevent devices which are coupled to the system
clocksource by implementing a less than or equal comparator which compares
the programmed absolute expiry time against the underlying time
counter. Well known examples are TSC/TSC deadline timer and the S390 TOD
clocksource/comparator.
While the concept is nice it has some downsides:
1) The clockevents core code is strictly based on relative expiry times
as that's the most common case for clockevent device hardware. That
requires to convert the absolute expiry time provided by the caller
(hrtimers, NOHZ code) to a relative expiry time by reading and
substracting the current time.
The clockevent::set_next_event() callback must then read the counter
again to convert the relative expiry back into a absolute one.
2) The conversion factors from nanoseconds to counter clock cycles are
set up when the clockevent is registered. When NTP applies corrections
then the clockevent conversion factors can deviate from the
clocksource conversion substantially which either results in timers
firing late or in the worst case early. The early expiry then needs to
do a reprogam with a short delta.
In most cases this is papered over by the fact that the read in the
set_next_event() callback happens after the read which is used to
calculate the delta. So the tendency is that timers expire mostly
late.
All of this can be avoided by providing support for these devices in the
core code:
1) The timekeeping core keeps track of the last update to the clocksource
by storing the base nanoseconds and the corresponding clocksource
counter value. That's used to keep the conversion math for reading the
time within 64-bit in the common case.
This information can be used to avoid both reads of the underlying
clocksource in the clockevents reprogramming path:
delta = expiry - base_ns;
cycles = base_cycles + ((delta * clockevent::mult) >> clockevent::shift);
The resulting cycles value can be directly used to program the
comparator.
2) As #1 does not longer provide the "compensation" through the second
read the deviation of the clocksource and clockevent conversions
caused by NTP become more prominent.
This can be cured by letting the timekeeping core compute and store
the reverse conversion factors when the clocksource cycles to
nanoseconds factors are modified by NTP:
CS::MULT (1 << NS_TO_CYC_SHIFT)
--------------- = ----------------------
(1 << CS:SHIFT) NS_TO_CYC_MULT
Ergo: NS_TO_CYC_MULT = (1 << (CS::SHIFT + NS_TO_CYC_SHIFT)) / CS::MULT
The NS_TO_CYC_SHIFT value is calculated when the clocksource is
installed so that it aims for a one hour maximum sleep time.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.944763521@kernel.org
On some architectures clocksource::read() boils down to a single
instruction, so the indirect function call is just a massive overhead
especially with speculative execution mitigations in effect.
Allow architectures to enable conditional inlining of that read to avoid
that by:
- providing a static branch to switch to the inlined variant
- disabling the branch before clocksource changes
- enabling the branch after a clocksource change, when the clocksource
indicates in a feature flag that it is the one which provides the
inlined variant
This is intentionally not a static call as that would only remove the
indirect call, but not the rest of the overhead.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.675151545@kernel.org
The only real usecase for this is the hrtimer based broadcast device.
No point in using two different feature flags for this.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.609049777@kernel.org
The sequence of cancel and start is inefficient. It has to do the timer
lock/unlock twice and in the worst case has to reprogram the underlying
clock event device twice.
The reason why it is done this way is the usage of hrtimer_forward_now(),
which requires the timer to be inactive.
But that can be completely avoided as the forward can be done on a variable
and does not need any of the overrun accounting provided by
hrtimer_forward_now().
Implement a trivial forwarding mechanism and replace the cancel/reprogram
sequence with hrtimer_start(..., new_expiry).
For the non high resolution case the timer is not actually armed, but used
for storage so that code checking for expiry times can unconditially look
it up in the timer. So it is safe for that case to set the new expiry time
directly.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.542178086@kernel.org
The hrtick timer is frequently rearmed before expiry and most of the time
the new expiry is past the armed one. As this happens on every context
switch it becomes expensive with scheduling heavy work loads especially in
virtual machines as the "hardware" reprogamming implies a VM exit.
Add a lazy rearm mode flag which skips the reprogamming if:
1) The timer was the first expiring timer before the rearm
2) The new expiry time is farther out than the armed time
This avoids a massive amount of reprogramming operations of the hrtick
timer for the price of eventually taking the alredy armed interrupt for
nothing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.408524456@kernel.org
The scheduler evaluates this via hrtimer_is_hres_active() every time it has
to update HRTICK. This needs to follow three pointers, which is expensive.
Provide a static branch based mechanism to avoid that.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.136503358@kernel.org
Much like hrtimer_reprogram(), skip programming if the cpu_base is running
the hrtimer interrupt.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260224163429.069535561@kernel.org
Add .kunitconfig file to the time directory to enable easy execution of
KUnit tests.
With the .kunitconfig, developers can run the tests:
$ ./tools/testing/kunit/kunit.py run --kunitconfig kernel/time
Also, add the new .kunitconfig file to the TIMEKEEPING section in the
MAINTAINERS file.
Signed-off-by: Ryota Sakamoto <sakamo.ryota@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260223-add-time-kunitconfig-v1-1-1801eeb33ece@gmail.com
The current cpuset partition code is able to dynamically update
the sched domains of a running system and the corresponding
HK_TYPE_DOMAIN housekeeping cpumask to perform what is essentially the
"isolcpus=domain,..." boot command line feature at run time.
The housekeeping cpumask update requires flushing a number of different
workqueues which may not be safe with cpus_read_lock() held as the
workqueue flushing code may acquire cpus_read_lock() or acquiring locks
which have locking dependency with cpus_read_lock() down the chain. Below
is an example of such circular locking problem.
======================================================
WARNING: possible circular locking dependency detected
6.18.0-test+ #2 Tainted: G S
------------------------------------------------------
test_cpuset_prs/10971 is trying to acquire lock:
ffff888112ba4958 ((wq_completion)sync_wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x7a/0x180
but task is already holding lock:
ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (cpuset_mutex){+.+.}-{4:4}:
-> #3 (cpu_hotplug_lock){++++}-{0:0}:
-> #2 (rtnl_mutex){+.+.}-{4:4}:
-> #1 ((work_completion)(&arg.work)){+.+.}-{0:0}:
-> #0 ((wq_completion)sync_wq){+.+.}-{0:0}:
Chain exists of:
(wq_completion)sync_wq --> cpu_hotplug_lock --> cpuset_mutex
5 locks held by test_cpuset_prs/10971:
#0: ffff88816810e440 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0xf9/0x1d0
#1: ffff8891ab620890 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x260/0x5f0
#2: ffff8890a78b83e8 (kn->active#187){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b6/0x5f0
#3: ffffffffadf32900 (cpu_hotplug_lock){++++}-{0:0}, at: cpuset_partition_write+0x77/0x130
#4: ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
Call Trace:
<TASK>
:
touch_wq_lockdep_map+0x93/0x180
__flush_workqueue+0x111/0x10b0
housekeeping_update+0x12d/0x2d0
update_parent_effective_cpumask+0x595/0x2440
update_prstate+0x89d/0xce0
cpuset_partition_write+0xc5/0x130
cgroup_file_write+0x1a5/0x680
kernfs_fop_write_iter+0x3df/0x5f0
vfs_write+0x525/0xfd0
ksys_write+0xf9/0x1d0
do_syscall_64+0x95/0x520
entry_SYSCALL_64_after_hwframe+0x76/0x7e
To avoid such a circular locking dependency problem, we have to
call housekeeping_update() without holding the cpus_read_lock() and
cpuset_mutex. The current set of wq's flushed by housekeeping_update()
may not have work functions that call cpus_read_lock() directly,
but we are likely to extend the list of wq's that are flushed in the
future. Moreover, the current set of work functions may hold locks that
may have cpu_hotplug_lock down the dependency chain.
So housekeeping_update() is now called after releasing cpus_read_lock
and cpuset_mutex at the end of a cpuset operation. These two locks are
then re-acquired later before calling rebuild_sched_domains_locked().
To enable mutual exclusion between the housekeeping_update() call and
other cpuset control file write actions, a new top level cpuset_top_mutex
is introduced. This new mutex will be acquired first to allow sharing
variables used by both code paths. However, cpuset update from CPU
hotplug can still happen in parallel with the housekeeping_update()
call, though that should be rare in production environment.
As cpus_read_lock() is now no longer held when
tmigr_isolated_exclude_cpumask() is called, it needs to acquire it
directly.
The lockdep_is_cpuset_held() is also updated to return true if either
cpuset_top_mutex or cpuset_mutex is held.
Fixes: 03ff735101 ("cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
* Removed macros from proc handler converters
Replace the proc converter macros with "regular" functions. Though it is more
verbose than the macro version, it helps when debugging and better aligns with
coding-style.rst.
* General cleanup
Remove superfluous ctl_table forward declarations. Const qualify the
memory_allocation_profiling_sysctl and loadpin_sysctl_table arrays. Add
missing kernel doc to proc_dointvec_conv.
* Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. And went into linux-next after rc4, giving it a good 3 weeks of
testing
-----BEGIN PGP SIGNATURE-----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=0Z+I
-----END PGP SIGNATURE-----
Merge tag 'sysctl-7.00-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl updates from Joel Granados:
- Remove macros from proc handler converters
Replace the proc converter macros with "regular" functions. Though it
is more verbose than the macro version, it helps when debugging and
better aligns with coding-style.rst.
- General cleanup
Remove superfluous ctl_table forward declarations. Const qualify the
memory_allocation_profiling_sysctl and loadpin_sysctl_table arrays.
Add missing kernel doc to proc_dointvec_conv.
- Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. And went into linux-next after rc4, giving it a good 3 weeks
of testing
* tag 'sysctl-7.00-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions
sysctl: Replace unidirectional INT converter macros with functions
sysctl: Add kernel doc to proc_douintvec_conv
sysctl: Replace UINT converter macros with functions
sysctl: Add CONFIG_PROC_SYSCTL guards for converter macros
sysctl: clarify proc_douintvec_minmax doc
sysctl: Return -ENOSYS from proc_douintvec_conv when CONFIG_PROC_SYSCTL=n
sysctl: Remove unused ctl_table forward declarations
loadpin: Implement custom proc_handler for enforce
alloc_tag: move memory_allocation_profiling_sysctls into .rodata
sysctl: Add missing kernel-doc for proc_dointvec_conv
For common cases (HZ=100, 250 or 1000), these helpers are at most one
multiply, so there is no point calling a tiny function.
Keep them out of line for HZ=300 and others.
This saves cycles in TCP fast path, among other things.
$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/8 grow/shrink: 25/89 up/down: 530/-3474 (-2944)
...
nla_put_msecs 193 - -193
message_stats_print 2131 920 -1211
Total: Before=25365208, After=25362264, chg -0.01%
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260210170226.57209-1-edumazet@google.com
- Inline timecounter_cyc2time() as that is now used in the networking
hotpath. Inlining it significantly improves performance.
- Optimize the tick dependency check in case that the tracepoint is disabled,
which improves the hotpath performance in the tick management code, which
is a hotpath on transitions in and out of idle.
- The usual cleanups and improvements
-----BEGIN PGP SIGNATURE-----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=Zh3T
-----END PGP SIGNATURE-----
Merge tag 'timers-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner:
- Inline timecounter_cyc2time() as that is now used in the networking
hotpath. Inlining it significantly improves performance.
- Optimize the tick dependency check in case that the tracepoint is
disabled, which improves the hotpath performance in the tick
management code, which is a hotpath on transitions in and out of
idle.
- The usual cleanups and improvements
* tag 'timers-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/kunit: Document handling of negative years of is_leap()
tick/nohz: Optimize check_tick_dependency() with early return
time/sched_clock: Use ACCESS_PRIVATE() to evaluate hrtimer::function
hrtimer: Drop _tv64() helpers
hrtimer: Remove public definition of HIGH_RES_NSEC
hrtimer: Remove unused resolution constants
time/timecounter: Inline timecounter_cyc2time()
Scheduler Kconfig space updates:
- Further consolidate configurable preemption modes: reduce
the number of architectures that are allowed to offer
PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number
of preemption models from four to just two: 'full' and 'lazy'
on up-to-date architectures (arm64, loongarch, powerpc,
riscv, s390, x86).
None and voluntary are only available as legacy features
on platforms that don't implement lazy preemption yet,
or which don't even support preemption.
The goal is to eventually remove cond_resched() and
voluntary preemption altogether.
(Peter Zijlstra)
RSEQ based 'scheduler time slice extension' support:
This allows a thread to request a time slice extension when it
enters a critical section to avoid contention on a resource when
the thread is scheduled out inside of the critical section.
- Add fields and constants for time slice extension
- Provide static branch for time slice extensions
- Add statistics for time slice extensions
- Add prctl() to enable time slice extensions
- Implement sys_rseq_slice_yield()
- Implement syscall entry work for time slice extensions
- Implement time slice extension enforcement timer
- Reset slice extension when scheduled
- Implement rseq_grant_slice_extension()
- entry: Hook up rseq time slice extension
- selftests: Implement time slice extension test
(Thomas Gleixner)
- Allow registering RSEQ with slice extension
- Move slice_ext_nsec to debugfs
- Lower default slice extension
- selftests/rseq: Add rseq slice histogram script
(Peter Zijlstra)
Scheduler performance/scalability improvements:
- Update rq->avg_idle when a task is moved to an idle CPU,
which improves the scalability of various workloads.
(Shubhang Kaushik)
- Reorder fields in 'struct rq' for better caching
(Blake Jones)
- Fair scheduler SMP NOHZ balancing code speedups:
- Move checking for nohz cpus after time check
- Change likelyhood of nohz.nr_cpus
- Remove nohz.nr_cpus and use weight of cpumask instead
(Shrikanth Hegde)
- Avoid false sharing for sched_clock_irqtime (Wangyang Guo)
- Drop useless cpumask_empty() in find_energy_efficient_cpu()
- Simplify task_numa_find_cpu()
- Use cpumask_weight_and() in sched_balance_find_dst_group()
(Yury Norov)
DL scheduler updates:
- Add a deadline server for sched_ext tasks (by Andrea Righi and
Joel Fernandes, with fixes by Peter Zijlstra)
RT scheduler updates:
- Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang)
Entry code updates and performance improvements, which is part of the
scheduler tree in this cycle due to interdependencies with the RSEQ
based time slice extension work:
- Remove unused syscall argument from syscall_trace_enter()
- Rework syscall_exit_to_user_mode_work() for architecture reuse
- Add arch_ptrace_report_syscall_entry/exit()
- Inline syscall_exit_work() and syscall_trace_enter()
(Jinjie Ruan)
Scheduler core updates:
- Rework sched_class::wakeup_preempt() and rq_modified_*()
- Avoid rq->lock bouncing in sched_balance_newidle()
- Rename rcu_dereference_check_sched_domain() =>
rcu_dereference_sched_domain()
- <linux/compiler_types.h>: Add the __signed_scalar_typeof() helper
(Peter Zijlstra)
Fair scheduler updates/refactoring:
- Fold the sched_avg update
- Change rcu_dereference_check_sched_domain() to rcu-sched
- Switch to rcu_dereference_all()
- Remove superfluous rcu_read_lock()
- Limit hrtick work
(Peter Zijlstra)
- Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks
- Clean up comments in 'struct cfs_rq'
- Separate se->vlag from se->vprot
- Rename cfs_rq::avg_load to cfs_rq::sum_weight
- Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions
- Introduce and use the vruntime_cmp() and vruntime_op() wrappers
for wrapped-signed aritmetics
- Sort out 'blocked_load*' namespace noise
(Ingo Molnar)
Scheduler debugging code updates:
- Export hidden tracepoints to modules (Gabriele Monaco)
- Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
(Fushuai Wang)
- Add assertions to QUEUE_CLASS (Peter Zijlstra)
- hrtimer: Fix tracing oddity (Thomas Gleixner)
Misc fixes and cleanups:
- Re-evaluate scheduling when migrating queued tasks out of
throttled cgroups (Zicheng Qu)
- Remove task_struct->faults_disabled_mapping (Christoph Hellwig)
- Fix math notation errors in avg_vruntime comment (Zhan Xusheng)
- sched/cpufreq: Use %pe format for PTR_ERR() printing (zenghongling)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=Xj2f
-----END PGP SIGNATURE-----
Merge tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Scheduler Kconfig space updates:
- Further consolidate configurable preemption modes (Peter Zijlstra)
Reduce the number of architectures that are allowed to offer
PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number of
preemption models from four to just two: 'full' and 'lazy' on
up-to-date architectures (arm64, loongarch, powerpc, riscv, s390,
x86).
None and voluntary are only available as legacy features on
platforms that don't implement lazy preemption yet, or which don't
even support preemption.
The goal is to eventually remove cond_resched() and voluntary
preemption altogether.
RSEQ based 'scheduler time slice extension' support (Thomas Gleixner
and Peter Zijlstra):
This allows a thread to request a time slice extension when it enters
a critical section to avoid contention on a resource when the thread
is scheduled out inside of the critical section.
- Add fields and constants for time slice extension
- Provide static branch for time slice extensions
- Add statistics for time slice extensions
- Add prctl() to enable time slice extensions
- Implement sys_rseq_slice_yield()
- Implement syscall entry work for time slice extensions
- Implement time slice extension enforcement timer
- Reset slice extension when scheduled
- Implement rseq_grant_slice_extension()
- entry: Hook up rseq time slice extension
- selftests: Implement time slice extension test
- Allow registering RSEQ with slice extension
- Move slice_ext_nsec to debugfs
- Lower default slice extension
- selftests/rseq: Add rseq slice histogram script
Scheduler performance/scalability improvements:
- Update rq->avg_idle when a task is moved to an idle CPU, which
improves the scalability of various workloads (Shubhang Kaushik)
- Reorder fields in 'struct rq' for better caching (Blake Jones)
- Fair scheduler SMP NOHZ balancing code speedups (Shrikanth Hegde):
- Move checking for nohz cpus after time check
- Change likelyhood of nohz.nr_cpus
- Remove nohz.nr_cpus and use weight of cpumask instead
- Avoid false sharing for sched_clock_irqtime (Wangyang Guo)
- Cleanups (Yury Norov):
- Drop useless cpumask_empty() in find_energy_efficient_cpu()
- Simplify task_numa_find_cpu()
- Use cpumask_weight_and() in sched_balance_find_dst_group()
DL scheduler updates:
- Add a deadline server for sched_ext tasks (by Andrea Righi and Joel
Fernandes, with fixes by Peter Zijlstra)
RT scheduler updates:
- Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang)
Entry code updates and performance improvements (Jinjie Ruan)
This is part of the scheduler tree in this cycle due to inter-
dependencies with the RSEQ based time slice extension work:
- Remove unused syscall argument from syscall_trace_enter()
- Rework syscall_exit_to_user_mode_work() for architecture reuse
- Add arch_ptrace_report_syscall_entry/exit()
- Inline syscall_exit_work() and syscall_trace_enter()
Scheduler core updates (Peter Zijlstra):
- Rework sched_class::wakeup_preempt() and rq_modified_*()
- Avoid rq->lock bouncing in sched_balance_newidle()
- Rename rcu_dereference_check_sched_domain() =>
rcu_dereference_sched_domain()
- <linux/compiler_types.h>: Add the __signed_scalar_typeof() helper
Fair scheduler updates/refactoring (Peter Zijlstra and Ingo Molnar):
- Fold the sched_avg update
- Change rcu_dereference_check_sched_domain() to rcu-sched
- Switch to rcu_dereference_all()
- Remove superfluous rcu_read_lock()
- Limit hrtick work
- Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks
- Clean up comments in 'struct cfs_rq'
- Separate se->vlag from se->vprot
- Rename cfs_rq::avg_load to cfs_rq::sum_weight
- Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions
- Introduce and use the vruntime_cmp() and vruntime_op() wrappers for
wrapped-signed aritmetics
- Sort out 'blocked_load*' namespace noise
Scheduler debugging code updates:
- Export hidden tracepoints to modules (Gabriele Monaco)
- Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
(Fushuai Wang)
- Add assertions to QUEUE_CLASS (Peter Zijlstra)
- hrtimer: Fix tracing oddity (Thomas Gleixner)
Misc fixes and cleanups:
- Re-evaluate scheduling when migrating queued tasks out of throttled
cgroups (Zicheng Qu)
- Remove task_struct->faults_disabled_mapping (Christoph Hellwig)
- Fix math notation errors in avg_vruntime comment (Zhan Xusheng)
- sched/cpufreq: Use %pe format for PTR_ERR() printing
(zenghongling)"
* tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
sched: Re-evaluate scheduling when migrating queued tasks out of throttled cgroups
sched/cpufreq: Use %pe format for PTR_ERR() printing
sched/rt: Skip currently executing CPU in rto_next_cpu()
sched/clock: Avoid false sharing for sched_clock_irqtime
selftests/sched_ext: Add test for DL server total_bw consistency
selftests/sched_ext: Add test for sched_ext dl_server
sched/debug: Fix dl_server (re)start conditions
sched/debug: Add support to change sched_ext server params
sched_ext: Add a DL server for sched_ext tasks
sched/debug: Stop and start server based on if it was active
sched/debug: Fix updating of ppos on server write ops
sched/deadline: Clear the defer params
entry: Inline syscall_exit_work() and syscall_trace_enter()
entry: Add arch_ptrace_report_syscall_entry/exit()
entry: Rework syscall_exit_to_user_mode_work() for architecture reuse
entry: Remove unused syscall argument from syscall_trace_enter()
sched: remove task_struct->faults_disabled_mapping
sched: Update rq->avg_idle when a task is moved to an idle CPU
selftests/rseq: Add rseq slice histogram script
hrtimer: Fix trace oddity
...
Lock debugging:
- Implement compiler-driven static analysis locking context
checking, using the upcoming Clang 22 compiler's context
analysis features. (Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context
tracking Sparse warnings, the overwhelming majority of which
are false positives. On an allmodconfig kernel the number of
false positive context tracking Sparse warnings grows to
over 5,200... On the plus side of the balance actual locking
bugs found by Sparse context analysis is also rather ... sparse:
I found only 3 such commits in the last 3 years. So the
rate of false positives and the maintenance overhead is
rather high and there appears to be no active policy in
place to achieve a zero-warnings baseline to move the
annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive
in trying to find bugs, at least in principle. Plus it has
a different model to enabling it: it's enabled subsystem by
subsystem, which results in zero warnings on all relevant
kernel builds (as far as our testing managed to cover it).
Which allowed us to enable it by default, similar to other
compiler warnings, with the expectation that there are no
warnings going forward. This enforces a zero-warnings baseline
on clang-22+ builds. (Which are still limited in distribution,
admittedly.)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more
subsystems and drivers enabling the feature. Context tracking
can be enabled for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y
(default disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional
function calls.
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline
(Arnd Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings
(Tamir Duberstein)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=N1gA
-----END PGP SIGNATURE-----
Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Lock debugging:
- Implement compiler-driven static analysis locking context checking,
using the upcoming Clang 22 compiler's context analysis features
(Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context tracking
Sparse warnings, the overwhelming majority of which are false
positives. On an allmodconfig kernel the number of false positive
context tracking Sparse warnings grows to over 5,200... On the plus
side of the balance actual locking bugs found by Sparse context
analysis is also rather ... sparse: I found only 3 such commits in
the last 3 years. So the rate of false positives and the
maintenance overhead is rather high and there appears to be no
active policy in place to achieve a zero-warnings baseline to move
the annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive in
trying to find bugs, at least in principle. Plus it has a different
model to enabling it: it's enabled subsystem by subsystem, which
results in zero warnings on all relevant kernel builds (as far as
our testing managed to cover it). Which allowed us to enable it by
default, similar to other compiler warnings, with the expectation
that there are no warnings going forward. This enforces a
zero-warnings baseline on clang-22+ builds (Which are still limited
in distribution, admittedly)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more subsystems
and drivers enabling the feature. Context tracking can be enabled
for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional function
calls
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John
Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
Duberstein)"
* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
rcu: Mark lockdep_assert_rcu_helper() __always_inline
compiler-context-analysis: Remove __assume_ctx_lock from initializers
tomoyo: Use scoped init guard
crypto: Use scoped init guard
kcov: Use scoped init guard
compiler-context-analysis: Introduce scoped init guards
cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
seqlock: fix scoped_seqlock_read kernel-doc
tools: Update context analysis macros in compiler_types.h
rust: sync: Replace `kernel::c_str!` with C-Strings
rust: sync: Inline various lock related methods
rust: helpers: Move #define __rust_helper out of atomic.c
rust: wait: Add __rust_helper to helpers
rust: time: Add __rust_helper to helpers
rust: task: Add __rust_helper to helpers
rust: sync: Add __rust_helper to helpers
rust: refcount: Add __rust_helper to helpers
rust: rcu: Add __rust_helper to helpers
rust: processor: Add __rust_helper to helpers
...
affinity of unbound kthreads (node or custom cpumask) against
housekeeping (CPU isolation) constraints and CPU hotplug events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset isolated
partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making nohz_full=
also mutable through cpuset in the future.
-----BEGIN PGP SIGNATURE-----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=nWGh
-----END PGP SIGNATURE-----
Merge tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull kthread updates from Frederic Weisbecker:
"The kthread code provides an infrastructure which manages the
preferred affinity of unbound kthreads (node or custom cpumask)
against housekeeping (CPU isolation) constraints and CPU hotplug
events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset
isolated partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making
nohz_full= also mutable through cpuset in the future"
* tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (33 commits)
doc: Add housekeeping documentation
kthread: Document kthread_affine_preferred()
kthread: Comment on the purpose and placement of kthread_affine_node() call
kthread: Honour kthreads preferred affinity after cpuset changes
sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN
sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN
kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management
kthread: Include kthreadd to the managed affinity list
kthread: Include unbound kthreads in the managed affinity list
kthread: Refine naming of affinity related fields
PCI: Remove superfluous HK_TYPE_WQ check
sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()
cpuset: Remove cpuset_cpu_is_isolated()
timers/migration: Remove superfluous cpuset isolation test
cpuset: Propagate cpuset isolation update to timers through housekeeping
cpuset: Propagate cpuset isolation update to workqueue through housekeeping
PCI: Flush PCI probe workqueue on cpuset isolated partition change
sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
sched/isolation: Flush memcg workqueues on cpuset isolated partition change
cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset
...
Cpuset isolated partitions are now included in HK_TYPE_DOMAIN. Testing
if a CPU is part of an isolated partition alone is now useless.
Remove the superflous test.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Testing housekeeping_cpu() will soon require that either the RCU "lock"
is held or the cpuset mutex.
When CPUs get isolated through cpuset, the change is propagated to
timer migration such that isolation is also performed from the migration
tree. However that propagation is done using workqueue which tests if
the target is actually isolated before proceeding.
Lockdep doesn't know that the workqueue caller holds cpuset mutex and
that it waits for the work, making the housekeeping cpumask read safe.
Shut down the future warning by removing this test. It is unecessary
beyond hotplug, the workqueue is already targeted towards isolated CPUs.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Gabriele Monaco <gmonaco@redhat.com>
The code local is_leap() helper was tried to be replaced by the RTC
is_leap_year() function. Unfortunately the two aren't exactly equivalent,
as the kunit variant uses a signed value for the year and the RTC an
unsigned one.
Since the KUnit tests cover a 16000 year range around the epoch they use
year values that are very comfortably negative and hence get mishandled
when passed into is_leap_year().
The change was reverted, so add a comment which prevents further attempts
to do so.
[ tglx: Adapted to the revert ]
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260130-kunit-fix-leap-year-v1-1-92ddf55dffd7@kernel.org
There is no point in iterating through individual tick dependency bits when
the tick_stop tracepoint is disabled, which is the common case.
When the trace point is disabled, return immediately based on the atomic
value being zero or non-zero, skipping the per-bit evaluation.
This optimization improves the hot path performance of tick dependency
checks across all contexts (idle and non-idle), not just nohz_full CPUs.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ionut Nechita (Sunlight Linux) <sunlightlinux@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260128074558.15433-3-sunlightlinux@gmail.com
cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
accounting has a nanoseconds granularity.
Use the appropriate indicator instead to make that deduction.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/aXozx0PXutnm8ECX@localhost.localdomain
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It turns out that __run_hrtimer() will trace like:
<idle>-0 [032] d.h2. 20705.474563: hrtimer_cancel: hrtimer=0xff2db8f77f8226e8
<idle>-0 [032] d.h1. 20705.474563: hrtimer_expire_entry: hrtimer=0xff2db8f77f8226e8 now=20699452001850 function=tick_nohz_handler/0x0
Which is a bit nonsensical, the timer doesn't get canceled on
expiration. The cause is the use of the incorrect debug helper.
Fixes: c6a2a17702 ("hrtimer: Add tracepoint for hrtimers")
Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121143208.219595606@infradead.org
The "valid" readout delay between the two reads of the watchdog is larger
than the valid delta between the resulting watchdog and clocksource
intervals, which results in false positive watchdog results.
Assume TSC is the clocksource and HPET is the watchdog and both have a
uncertainty margin of 250us (default). The watchdog readout does:
1) wdnow = read(HPET);
2) csnow = read(TSC);
3) wdend = read(HPET);
The valid window for the delta between #1 and #3 is calculated by the
uncertainty margins of the watchdog and the clocksource:
m = 2 * watchdog.uncertainty_margin + cs.uncertainty margin;
which results in 750us for the TSC/HPET case.
The actual interval comparison uses a smaller margin:
m = watchdog.uncertainty_margin + cs.uncertainty margin;
which results in 500us for the TSC/HPET case.
That means the following scenario will trigger the watchdog:
Watchdog cycle N:
1) wdnow[N] = read(HPET);
2) csnow[N] = read(TSC);
3) wdend[N] = read(HPET);
Assume the delay between #1 and #2 is 100us and the delay between #1 and
Watchdog cycle N + 1:
4) wdnow[N + 1] = read(HPET);
5) csnow[N + 1] = read(TSC);
6) wdend[N + 1] = read(HPET);
If the delay between #4 and #6 is within the 750us margin then any delay
between #4 and #5 which is larger than 600us will fail the interval check
and mark the TSC unstable because the intervals are calculated against the
previous value:
wd_int = wdnow[N + 1] - wdnow[N];
cs_int = csnow[N + 1] - csnow[N];
Putting the above delays in place this results in:
cs_int = (wdnow[N + 1] + 610us) - (wdnow[N] + 100us);
-> cs_int = wd_int + 510us;
which is obviously larger than the allowed 500us margin and results in
marking TSC unstable.
Fix this by using the same margin as the interval comparison. If the delay
between two watchdog reads is larger than that, then the readout was either
disturbed by interconnect congestion, NMIs or SMIs.
Fixes: 4ac1dd3245 ("clocksource: Set cs_watchdog_read() checks based on .uncertainty_margin")
Reported-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/lkml/20250602223251.496591-1-daniel@quora.org/
Link: https://patch.msgid.link/87bjjxc9dq.ffs@tglx
When __do_ajdtimex() was introduced to handle adjtimex for any
timekeeper, this reference to tk_core was not updated. When called on an
auxiliary timekeeper, the core timekeeper would be updated incorrectly.
This gets caught by the lock debugging diagnostics because the
timekeepers sequence lock gets written to without holding its
associated spinlock:
WARNING: include/linux/seqlock.h:226 at __do_adjtimex+0x394/0x3b0, CPU#2: test/125
aux_clock_adj (kernel/time/timekeeping.c:2979)
__do_sys_clock_adjtime (kernel/time/posix-timers.c:1161 kernel/time/posix-timers.c:1173)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)
Update the correct auxiliary timekeeper.
Fixes: 775f71ebed ("timekeeping: Make do_adjtimex() reusable")
Fixes: ecf3e70304 ("timekeeping: Provide adjtimex() for auxiliary clocks")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260120-timekeeper-auxclock-leapstate-v1-1-5b358c6b3cfd@linutronix.de
Since ktime_t has become an alias to s64, these helpers are unnecessary.
Migrate the few remaining users to the regular helpers and remove the
now dead code.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260107-hrtimer-header-cleanup-v1-3-1a698ef0ddae@linutronix.de
This constant is only used in a single place and is has a very generic
name polluting the global namespace.
Move the constant closer to its only user.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260107-hrtimer-header-cleanup-v1-2-1a698ef0ddae@linutronix.de
In a vain attempt to consolidate the email zoo switch everything to the
kernel.org account.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove SYSCTL_INT_CONV_CUSTOM and replace it with proc_int_conv. This
converter function expects a negp argument as it can take on negative
values. Update all jiffies converters to use explicit function calls.
Remove SYSCTL_CONV_IDENTITY as it is no longer used.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
Replace SYSCTL_USER_TO_KERN_INT_CONV and SYSCTL_KERN_TO_USER_INT_CONV
macros with function implementing the same logic.This makes debugging
easier and aligns with the functions preference described in
coding-style.rst. Update all jiffies converters to use explicit function
implementations instead of macro-generated versions.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
As discussed in [1], removing __cond_lock() will improve the readability
of trylock code. Now that Sparse context tracking support has been
removed, we can also remove __cond_lock().
Change existing APIs to either drop __cond_lock() completely, or make
use of the __cond_acquires() function attribute instead.
In particular, spinlock and rwlock implementations required switching
over to inline helpers rather than statement-expressions for their
trylock_* variants.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250207082832.GU7145@noisy.programming.kicks-ass.net/ [1]
Link: https://patch.msgid.link/20251219154418.3592607-25-elver@google.com
