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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- Jump label fixes, including a perf events fix that originally
manifested as jump label failures, but was a serialization bug at the
usage site
- Mark down_write*() helpers as __always_inline, to improve WCHAN
debuggability
- Misc cleanups and fixes
* tag 'locking-core-2024-07-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwsem: Add __always_inline annotation to __down_write_common() and inlined callers
jump_label: Simplify and clarify static_key_fast_inc_cpus_locked()
jump_label: Clarify condition in static_key_fast_inc_not_disabled()
jump_label: Fix concurrency issues in static_key_slow_dec()
perf/x86: Serialize set_attr_rdpmc()
cleanup: Standardize the header guard define's name
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git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl updates from Joel Granados:
- Remove "->procname == NULL" check when iterating through sysctl table
arrays
Removing sentinels in ctl_table arrays reduces the build time size
and runtime memory consumed by ~64 bytes per array. With all
ctl_table sentinels gone, the additional check for ->procname == NULL
that worked in tandem with the ARRAY_SIZE to calculate the size of
the ctl_table arrays is no longer needed and has been removed. The
sysctl register functions now returns an error if a sentinel is used.
- Preparation patches for sysctl constification
Constifying ctl_table structs prevents the modification of
proc_handler function pointers as they would reside in .rodata. The
ctl_table arguments in sysctl utility functions are const qualified
in preparation for a future treewide proc_handler argument
constification commit.
- Misc fixes
Increase robustness of set_ownership by providing sane default
ownership values in case the callee doesn't set them. Bound check
proc_dou8vec_minmax to avoid loading buggy modules and give sysctl
testing module a name to avoid compiler complaints.
* tag 'sysctl-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
sysctl: Warn on an empty procname element
sysctl: Remove ctl_table sentinel code comments
sysctl: Remove "child" sysctl code comments
sysctl: Remove superfluous empty allocations from sysctl internals
sysctl: Replace nr_entries with ctl_table_size in new_links
sysctl: Remove check for sentinel element in ctl_table arrays
mm profiling: Remove superfluous sentinel element from ctl_table
locking: Remove superfluous sentinel element from kern_lockdep_table
sysctl: Add module description to sysctl-testing
sysctl: constify ctl_table arguments of utility function
utsname: constify ctl_table arguments of utility function
sysctl: move the extra1/2 boundary check of u8 to sysctl_check_table_array
sysctl: always initialize i_uid/i_gid
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- some trivial cleanups
- a fix for the Xen timer
- add boot time selectable debug capability to the Xen multicall
handling
- two fixes for the recently added Xen irqfd handling
* tag 'for-linus-6.11-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen: remove deprecated xen_nopvspin boot parameter
x86/xen: eliminate some private header files
x86/xen: make some functions static
xen: make multicall debug boot time selectable
xen/arm: Convert comma to semicolon
xen: privcmd: Fix possible access to a freed kirqfd instance
xen: privcmd: Switch from mutex to spinlock for irqfds
xen: add missing MODULE_DESCRIPTION() macros
x86/xen: Convert comma to semicolon
x86/xen/time: Reduce Xen timer tick
xen/manage: Constify struct shutdown_handler
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The xen_nopvspin boot parameter is deprecated since 2019. nopvspin
can be used instead.
Remove the xen_nopvspin boot parameter and replace the xen_pvspin
variable use cases with nopvspin.
This requires to move the nopvspin variable out of the .initdata
section, as it needs to be accessed for cpuhotplug, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <20240710110139.22300-1-jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
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inlined callers
Apparently despite it being marked inline, the compiler
may not inline __down_write_common() which makes it difficult
to identify the cause of lock contention, as the wchan of the
blocked function will always be listed as __down_write_common().
So add __always_inline annotation to the common function (as
well as the inlined helper callers) to force it to be inlined
so a more useful blocking function will be listed (via wchan).
This mirrors commit 92cc5d00a431 ("locking/rwsem: Add
__always_inline annotation to __down_read_common() and inlined
callers") which did the same for __down_read_common.
I sort of worry that I'm playing wack-a-mole here, and talking
with compiler people, they tell me inline means nothing, which
makes me want to cry a little. So I'm wondering if we need to
replace all the inlines with __always_inline, or remove them
because either we mean something by it, or not.
Fixes: c995e638ccbb ("locking/rwsem: Fold __down_{read,write}*()")
Reported-by: Tim Murray <timmurray@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20240709060831.495366-1-jstultz@google.com
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This commit is part of a greater effort to remove all
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
Signed-off-by: Joel Granados <j.granados@samsung.com>
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Fix the 'make W=1' warning:
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/locking/locktorture.o
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/lee/leds
Pull LED updates from Lee Jones:
"Core Frameworks:
- Ensure seldom updated triggers have a brightness value before first
update
New Device Support:
- Add support for Simatic IPC Device BX_59A to IPC LEDs Core
- Add support for Qualcomm PMI8950 PWM to LPG Core
New Functionality:
- Add a bunch of new LED function identifiers
- Add support for High Resolution Timers in LED Trigger Patten
Fix-ups:
- Shift out Audio Trigger to the Sound subsystem
- Convert suitable calls to devm_* managed resources
- Device Tree binding adaptions/conversions/creation
- Remove superfluous code/variables/attributes and simplify overall
- Use/convert to new/better APIs/helpers/MACROs instead of
hand-rolling implementations
Bug Fixes:
- Repair enabling Torch Mode from V4L2 on the second LED
- Ensure PWM is disabled when suspending"
* tag 'leds-next-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/leds: (28 commits)
leds: mt6370: Remove unused field 'reg_cfgs' from 'struct mt6370_priv'
leds: lp50xx: Remove unused field 'num_of_banked_leds' from 'struct lp50xx'
leds: lp50xx: Remove unused field 'bank_modules' from 'struct lp50xx_led'
leds: aat1290: Remove unused field 'torch_brightness' from 'struct aat1290_led'
leds: sun50i-a100: Use match_string() helper to simplify the code
leds: pwm: Disable PWM when going to suspend
leds: trigger: pattern: Add support for hrtimer
leds: mt6360: Fix the second LED can not enable torch mode by V4L2
dt-bindings: leds: leds-qcom-lpg: Add support for PMI8950 PWM
leds: qcom-lpg: Add support for PMI8950 PWM
leds: apu: Remove duplicate DMI lookup data
leds: trigger: netdev: Remove not needed call to led_set_brightness in deactivate
dt-bindings: leds: Add LED_FUNCTION_SPEED_* for link speed on LAN/WAN
dt-bindings: leds: Add LED_FUNCTION_MOBILE for mobile network
leds: simatic-ipc-leds-gpio: Add support for module BX-59A
dt-bindings: leds: qcom-lpg: Document PM6150L compatible
dt-bindings: leds: pca963x: Convert text bindings to YAML
leds: an30259a: Use devm_mutex_init() for mutex initialization
leds: mlxreg: Use devm_mutex_init() for mutex initialization
leds: nic78bx: Use devm API to cleanup module's resources
...
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Use try_cmpxchg(*ptr, &old, new) instead of
cmpxchg(*ptr, old, new) == old in qspinlock_paravirt.h
x86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240411192317.25432-2-ubizjak@gmail.com
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Replace this pattern in trylock_clear_pending():
cmpxchg_acquire(*ptr, old, new) == old
... with the simpler and faster:
try_cmpxchg_acquire(*ptr, &old, new)
The x86 CMPXCHG instruction returns success in the ZF flag, so this change
saves a compare after the CMPXCHG.
Also change the return type of the function to bool and streamline
the control flow in the _Q_PENDING_BITS == 8 variant a bit.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240325140943.815051-1-ubizjak@gmail.com
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Using of devm API leads to a certain order of releasing resources.
So all dependent resources which are not devm-wrapped should be deleted
with respect to devm-release order. Mutex is one of such objects that
often is bound to other resources and has no own devm wrapping.
Since mutex_destroy() actually does nothing in non-debug builds
frequently calling mutex_destroy() is just ignored which is safe for now
but wrong formally and can lead to a problem if mutex_destroy() will be
extended so introduce devm_mutex_init().
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20240411161032.609544-2-gnstark@salutedevices.com
Signed-off-by: Lee Jones <lee@kernel.org>
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Use atomic_try_cmpxchg_relaxed(*ptr, &old, new) instead of
atomic_cmpxchg_relaxed (*ptr, old, new) == old in xchg_tail().
x86 CMPXCHG instruction returns success in ZF flag,
so this change saves a compare after CMPXCHG.
No functional change intended.
Since this code requires NR_CPUS >= 16k, I have tested it
by unconditionally setting _Q_PENDING_BITS to 1 in
<asm-generic/qspinlock_types.h>.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240321195309.484275-1-ubizjak@gmail.com
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The 'inc' parameter of lockevent_add() and the cond parameter of
lockevent_cond_inc() are only evaluated when CONFIG_LOCK_EVENT_COUNTS
is on. That can cause problem if those parameters are expressions
with side effect like a "++". Fix this by evaluating those non-event
parameters once even if CONFIG_LOCK_EVENT_COUNTS is off. This will also
eliminate the need of the __maybe_unused attribute to the wait_early
local variable in pv_wait_node().
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240319005004.1692705-1-longman@redhat.com
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Use try_cmpxchg() instead of cmpxchg(*ptr, old, new) == old.
The x86 CMPXCHG instruction returns success in the ZF flag, so this change
saves a compare after CMPXCHG (and related move instruction in front of CMPXCHG).
Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when CMPXCHG
fails. There is no need to re-read the value in the loop.
Note that the value from *ptr should be read using READ_ONCE() to prevent
the compiler from merging, refetching or reordering the read.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240124104953.612063-1-ubizjak@gmail.com
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We mistakenly always fire lock contention tracepoints in the writer path,
while it should be conditional on the trylock result.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20231108215322.2845536-1-namhyung@kernel.org
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Clarify in the comments that the RWSEM_READER_OWNED bit in the owner
field is just a hint, not an authoritative state of the rwsem.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240222150540.79981-4-longman@redhat.com
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When CONFIG_LOCK_EVENT_COUNTS is off, the wait_early variable will be
set but not used. This is expected. Recent compilers will not generate
wait_early code in this case.
Add the __maybe_unused attribute to wait_early for suppressing this
W=1 warning.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240222150540.79981-2-longman@redhat.com
Closes: https://lore.kernel.org/oe-kbuild-all/202312260422.f4pK3f9m-lkp@intel.com/
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Pull RCU updates from Neeraj Upadhyay:
- Documentation and comment updates
- RCU torture, locktorture updates that include cleanups; nolibc init
build support for mips, ppc and rv64; testing of mid stall duration
scenario and fixing fqs task creation conditions
- Misc fixes, most notably restricting usage of RCU CPU stall
notifiers, to confine their usage primarily to debug kernels
- RCU tasks minor fixes
- lockdep annotation fix for NMI-safe accesses, callback
advancing/acceleration cleanup and documentation improvements
* tag 'rcu.release.v6.8' of https://github.com/neeraju/linux:
rcu: Force quiescent states only for ongoing grace period
doc: Clarify historical disclaimers in memory-barriers.txt
doc: Mention address and data dependencies in rcu_dereference.rst
doc: Clarify RCU Tasks reader/updater checklist
rculist.h: docs: Fix wrong function summary
Documentation: RCU: Remove repeated word in comments
srcu: Use try-lock lockdep annotation for NMI-safe access.
srcu: Explain why callbacks invocations can't run concurrently
srcu: No need to advance/accelerate if no callback enqueued
srcu: Remove superfluous callbacks advancing from srcu_gp_start()
rcu: Remove unused macros from rcupdate.h
rcu: Restrict access to RCU CPU stall notifiers
rcu-tasks: Mark RCU Tasks accesses to current->rcu_tasks_idle_cpu
rcutorture: Add fqs_holdoff check before fqs_task is created
rcutorture: Add mid-sized stall to TREE07
rcutorture: add nolibc init support for mips, ppc and rv64
locktorture: Increase Hamming distance between call_rcu_chain and rcu_call_chains
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Pull header cleanups from Kent Overstreet:
"The goal is to get sched.h down to a type only header, so the main
thing happening in this patchset is splitting out various _types.h
headers and dependency fixups, as well as moving some things out of
sched.h to better locations.
This is prep work for the memory allocation profiling patchset which
adds new sched.h interdepencencies"
* tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs: (51 commits)
Kill sched.h dependency on rcupdate.h
kill unnecessary thread_info.h include
Kill unnecessary kernel.h include
preempt.h: Kill dependency on list.h
rseq: Split out rseq.h from sched.h
LoongArch: signal.c: add header file to fix build error
restart_block: Trim includes
lockdep: move held_lock to lockdep_types.h
sem: Split out sem_types.h
uidgid: Split out uidgid_types.h
seccomp: Split out seccomp_types.h
refcount: Split out refcount_types.h
uapi/linux/resource.h: fix include
x86/signal: kill dependency on time.h
syscall_user_dispatch.h: split out *_types.h
mm_types_task.h: Trim dependencies
Split out irqflags_types.h
ipc: Kill bogus dependency on spinlock.h
shm: Slim down dependencies
workqueue: Split out workqueue_types.h
...
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Pick up these commits from Linus's tree:
b106bcf0f99a ("locking/osq_lock: Clarify osq_wait_next()")
563adbfc351b ("locking/osq_lock: Clarify osq_wait_next() calling convention")
7c2230982129 ("locking/osq_lock: Move the definition of optimistic_spin_node into osq_lock.c")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Directly return NULL or 'next' instead of breaking out of the loop.
Signed-off-by: David Laight <david.laight@aculab.com>
[ Split original patch into two independent parts - Linus ]
Link: https://lore.kernel.org/lkml/7c8828aec72e42eeb841ca0ee3397e9a@AcuMS.aculab.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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osq_wait_next() is passed 'prev' from osq_lock() and NULL from
osq_unlock() but only needs the 'cpu' value to write to lock->tail.
Just pass prev->cpu or OSQ_UNLOCKED_VAL instead.
Should have no effect on the generated code since gcc manages to assume
that 'prev != NULL' due to an earlier dereference.
Signed-off-by: David Laight <david.laight@aculab.com>
[ Changed 'old' to 'old_cpu' by request from Waiman Long - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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struct optimistic_spin_node is private to the implementation.
Move it into the C file to ensure nothing is accessing it.
Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is needed for killing the sched.h dependency on rcupdate.h, and
pid.h is a better place for this code anyways.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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I have seen several cases of attempts to use mutex_unlock() to release an
object such that the object can then be freed by another task.
This is not safe because mutex_unlock(), in the
MUTEX_FLAG_WAITERS && !MUTEX_FLAG_HANDOFF case, accesses the mutex
structure after having marked it as unlocked; so mutex_unlock() requires
its caller to ensure that the mutex stays alive until mutex_unlock()
returns.
If MUTEX_FLAG_WAITERS is set and there are real waiters, those waiters
have to keep the mutex alive, but we could have a spurious
MUTEX_FLAG_WAITERS left if an interruptible/killable waiter bailed
between the points where __mutex_unlock_slowpath() did the cmpxchg
reading the flags and where it acquired the wait_lock.
( With spinlocks, that kind of code pattern is allowed and, from what I
remember, used in several places in the kernel. )
Document this, such a semantic difference between mutexes and spinlocks
is fairly unintuitive.
[ mingo: Made the changelog a bit more assertive, refined the comments. ]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231130204817.2031407-1-jannh@google.com
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Kent reported an occasional KASAN splat in lockdep. Mark then noted:
> I suspect the dodgy access is to chain_block_buckets[-1], which hits the last 4
> bytes of the redzone and gets (incorrectly/misleadingly) attributed to
> nr_large_chain_blocks.
That would mean @size == 0, at which point size_to_bucket() returns -1
and the above happens.
alloc_chain_hlocks() has 'size - req', for the first with the
precondition 'size >= rq', which allows the 0.
This code is trying to split a block, del_chain_block() takes what we
need, and add_chain_block() puts back the remainder, except in the
above case the remainder is 0 sized and things go sideways.
Fixes: 810507fe6fd5 ("locking/lockdep: Reuse freed chain_hlocks entries")
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lkml.kernel.org/r/20231121114126.GH8262@noisy.programming.kicks-ass.net
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rcu_call_chains
One letter difference is really not enough, so this commit changes
call_rcu_chain to call_rcu_chain_list.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull RCU updates from Frederic Weisbecker:
- RCU torture, locktorture and generic torture infrastructure updates
that include various fixes, cleanups and consolidations.
Among the user visible things, ftrace dumps can now be found into
their own file, and module parameters get better documented and
reported on dumps.
- Generic and misc fixes all over the place. Some highlights:
* Hotplug handling has seen some light cleanups and comments
* An RCU barrier can now be triggered through sysfs to serialize
memory stress testing and avoid OOM
* Object information is now dumped in case of invalid callback
invocation
* Also various SRCU issues, too hard to trigger to deserve urgent
pull requests, have been fixed
- RCU documentation updates
- RCU reference scalability test minor fixes and doc improvements.
- RCU tasks minor fixes
- Stall detection updates. Introduce RCU CPU Stall notifiers that
allows a subsystem to provide informations to help debugging. Also
cure some false positive stalls.
* tag 'rcu-next-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (56 commits)
srcu: Only accelerate on enqueue time
locktorture: Check the correct variable for allocation failure
srcu: Fix callbacks acceleration mishandling
rcu: Comment why callbacks migration can't wait for CPUHP_RCUTREE_PREP
rcu: Standardize explicit CPU-hotplug calls
rcu: Conditionally build CPU-hotplug teardown callbacks
rcu: Remove references to rcu_migrate_callbacks() from diagrams
rcu: Assume rcu_report_dead() is always called locally
rcu: Assume IRQS disabled from rcu_report_dead()
rcu: Use rcu_segcblist_segempty() instead of open coding it
rcu: kmemleak: Ignore kmemleak false positives when RCU-freeing objects
srcu: Fix srcu_struct node grpmask overflow on 64-bit systems
torture: Convert parse-console.sh to mktemp
rcutorture: Traverse possible cpu to set maxcpu in rcu_nocb_toggle()
rcutorture: Replace schedule_timeout*() 1-jiffy waits with HZ/20
torture: Add kvm.sh --debug-info argument
locktorture: Rename readers_bind/writers_bind to bind_readers/bind_writers
doc: Catch-up update for locktorture module parameters
locktorture: Add call_rcu_chains module parameter
locktorture: Add new module parameters to lock_torture_print_module_parms()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Info Molnar:
"Futex improvements:
- Add the 'futex2' syscall ABI, which is an attempt to get away from
the multiplex syscall and adds a little room for extentions, while
lifting some limitations.
- Fix futex PI recursive rt_mutex waiter state bug
- Fix inter-process shared futexes on no-MMU systems
- Use folios instead of pages
Micro-optimizations of locking primitives:
- Improve arch_spin_value_unlocked() on asm-generic ticket spinlock
architectures, to improve lockref code generation
- Improve the x86-32 lockref_get_not_zero() main loop by adding
build-time CMPXCHG8B support detection for the relevant lockref
code, and by better interfacing the CMPXCHG8B assembly code with
the compiler
- Introduce arch_sync_try_cmpxchg() on x86 to improve
sync_try_cmpxchg() code generation. Convert some sync_cmpxchg()
users to sync_try_cmpxchg().
- Micro-optimize rcuref_put_slowpath()
Locking debuggability improvements:
- Improve CONFIG_DEBUG_RT_MUTEXES=y to have a fast-path as well
- Enforce atomicity of sched_submit_work(), which is de-facto atomic
but was un-enforced previously.
- Extend <linux/cleanup.h>'s no_free_ptr() with __must_check
semantics
- Fix ww_mutex self-tests
- Clean up const-propagation in <linux/seqlock.h> and simplify the
API-instantiation macros a bit
RT locking improvements:
- Provide the rt_mutex_*_schedule() primitives/helpers and use them
in the rtmutex code to avoid recursion vs. rtlock on the PI state.
- Add nested blocking lockdep asserts to rt_mutex_lock(),
rtlock_lock() and rwbase_read_lock()
.. plus misc fixes & cleanups"
* tag 'locking-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
futex: Don't include process MM in futex key on no-MMU
locking/seqlock: Fix grammar in comment
alpha: Fix up new futex syscall numbers
locking/seqlock: Propagate 'const' pointers within read-only methods, remove forced type casts
locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning
locking/seqlock: Change __seqprop() to return the function pointer
locking/seqlock: Simplify SEQCOUNT_LOCKNAME()
locking/atomics: Use atomic_try_cmpxchg_release() to micro-optimize rcuref_put_slowpath()
locking/atomic, xen: Use sync_try_cmpxchg() instead of sync_cmpxchg()
locking/atomic/x86: Introduce arch_sync_try_cmpxchg()
locking/atomic: Add generic support for sync_try_cmpxchg() and its fallback
locking/seqlock: Fix typo in comment
futex/requeue: Remove unnecessary ‘NULL’ initialization from futex_proxy_trylock_atomic()
locking/local, arch: Rewrite local_add_unless() as a static inline function
locking/debug: Fix debugfs API return value checks to use IS_ERR()
locking/ww_mutex/test: Make sure we bail out instead of livelock
locking/ww_mutex/test: Fix potential workqueue corruption
locking/ww_mutex/test: Use prng instead of rng to avoid hangs at bootup
futex: Add sys_futex_requeue()
futex: Add flags2 argument to futex_requeue()
...
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The bcachefs implementation of six locks is intended to land in
generic locking code in the long term, but has been pulled into the
bcachefs subsystem for internal use for the time being. This code
lift breaks the bcachefs module build as six locks depend a couple
of the generic locking tracepoints. Export these tracepoint symbols
for bcachefs.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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compiler-warning
On an allyesconfig, with "treat warnings as errors" unset, GCC emits
these warnings:
kernel/locking/lockdep_proc.c:438:32: Warning: Format specifier '%lld' may
be truncated when writing 1 to 17 bytes into a region
of size 15 [-Wformat-truncation=]
kernel/locking/lockdep_proc.c:438:31: Note: Format directive argument is
in the range [-9223372036854775, 9223372036854775]
kernel/locking/lockdep_proc.c:438:9: Note: 'snprintf' has output
between 5 and 22 bytes into a target of size 15
In seq_time(), the longest s64 is "-9223372036854775808"-ish, which
converted to the fixed-point float format is "-9223372036854775.80": 21 bytes,
plus termination is another byte: 22. Therefore, a larger buffer size
of 22 is needed here - not 15. The code was safe due to the snprintf().
Fix it.
Signed-off-by: Lucy Mielke <lucymielke@icloud.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/ZSfOEHRkZAWaQr3U@fedora.fritz.box
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There is a typo so this checks the wrong variable. "chains" plural vs
"chain" singular. We already know that "chains" is non-zero.
Fixes: 7f993623e9eb ("locktorture: Add call_rcu_chains module parameter")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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Update the checking of return values from debugfs_create_file()
and debugfs_create_dir() to use IS_ERR().
Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20230807121834.7438-1-atulpant.linux@gmail.com
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This commit renames the readers_bind and writers_bind module parameters
to bind_readers and bind_writers, respectively. This provides added
clarity via the imperative mode and better organizes the documentation.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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When running locktorture on large systems, there will normally be
enough RCU activity to ensure that there is a grace period in flight
at all times. However, on smaller systems, RCU might well be idle the
majority of the time. This situation can be inconvenient in cases where
the RCU CPU stall warning is part of the debugging process.
This commit therefore adds an call_rcu_chains module parameter to
locktorture, allowing the user to specify the desired number of
self-propagating call_rcu() chains. For good measure, immediately
before invoking call_rcu(), the self-propagating RCU callback invokes
start_poll_synchronize_rcu() to force the immediate start of a grace
period, with the call_rcu() forcing another to start shortly thereafter.
Booting with locktorture.call_rcu_chains=2 increases the probability
of a stuck locking primitive resulting in an RCU CPU stall warning from
about 25% to nearly 100%.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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This commit adds new module parameters to lock_torture_print_module_parms,
and alphabetizes things while in the area. This change makes locktorture
test results more useful and self-contained.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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This commit adds a locktorture.acq_writer_lim module parameter that
specifies the maximum number of jiffies that is expected to be consumed
by write-side lock acquisition. If this limit is exceeded, a WARN_ONCE()
causes a splat. Note that this limit applies to the main lock acquisition
only, not to any nested acquisitions.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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There is a pair of adjacent "if" statements with identical conditions in
the lock_torture_writer() function. This commit therefore combines them.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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There are getting to be too many module parameters for a random list to be
comfortable, so this commit alphabetizes the list. Strictly code motion.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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This commit adds readers_bind and writers_bind module parameters to
locktorture in order to skew tests across socket boundaries. This skewing
is intended to provide additional variable-latency stress on the primitive
under test.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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I've seen what appears to be livelocks in the stress_inorder_work()
function, and looking at the code it is clear we can have a case
where we continually retry acquiring the locks and never check to
see if we have passed the specified timeout.
This patch reworks that function so we always check the timeout
before iterating through the loop again.
I believe others may have hit this previously here:
https://lore.kernel.org/lkml/895ef450-4fb3-5d29-a6ad-790657106a5a@intel.com/
Reported-by: Li Zhijian <zhijianx.li@intel.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-4-jstultz@google.com
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In some cases running with the test-ww_mutex code, I was seeing
odd behavior where sometimes it seemed flush_workqueue was
returning before all the work threads were finished.
Often this would cause strange crashes as the mutexes would be
freed while they were being used.
Looking at the code, there is a lifetime problem as the
controlling thread that spawns the work allocates the
"struct stress" structures that are passed to the workqueue
threads. Then when the workqueue threads are finished,
they free the stress struct that was passed to them.
Unfortunately the workqueue work_struct node is in the stress
struct. Which means the work_struct is freed before the work
thread returns and while flush_workqueue is waiting.
It seems like a better idea to have the controlling thread
both allocate and free the stress structures, so that we can
be sure we don't corrupt the workqueue by freeing the structure
prematurely.
So this patch reworks the test to do so, and with this change
I no longer see the early flush_workqueue returns.
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-3-jstultz@google.com
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Booting w/ qemu without kvm, and with 64 cpus, I noticed we'd
sometimes hung task watchdog splats in get_random_u32_below()
when using the test-ww_mutex stress test.
While entropy exhaustion is no longer an issue, the RNG may be
slower early in boot. The test-ww_mutex code will spawn off
128 threads (2x cpus) and each thread will call
get_random_u32_below() a number of times to generate a random
order of the 16 locks.
This intense use takes time and without kvm, qemu can be slow
enough that we trip the hung task watchdogs.
For this test, we don't need true randomness, just mixed up
orders for testing ww_mutex lock acquisitions, so it changes
the logic to use the prng instead, which takes less time
and avoids the watchdgos.
Feedback would be appreciated!
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-2-jstultz@google.com
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There used to be a BUG_ON(current->pi_blocked_on) in the lock acquisition
functions, but that vanished in one of the rtmutex overhauls.
Bring it back in form of a lockdep assert to catch code paths which take
rtmutex based locks with current::pi_blocked_on != NULL.
Reported-by: Crystal Wood <swood@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-7-bigeasy@linutronix.de
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Have rt_mutex use the rt_mutex specific scheduler helpers to avoid
recursion vs rtlock on the PI state.
[[ peterz: adapted to new names ]]
Reported-by: Crystal Wood <swood@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-6-bigeasy@linutronix.de
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With DEBUG_RT_MUTEXES enabled the fast-path rt_mutex_cmpxchg_acquire()
always fails and all lock operations take the slow path.
Provide a new helper inline rt_mutex_try_acquire() which maps to
rt_mutex_cmpxchg_acquire() in the non-debug case. For the debug case
it invokes rt_mutex_slowtrylock() which can acquire a non-contended
rtmutex under full debug coverage.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-3-bigeasy@linutronix.de
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from Eric DeVolder
("refactor Kconfig to consolidate KEXEC and CRASH options")
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
couple of macros to args.h")
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
commands")
- vsprintf inclusion rationalization from Andy Shevchenko
("lib/vsprintf: Rework header inclusions")
- Switch the handling of kdump from a udev scheme to in-kernel
handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
hot un/plug")
- Many singleton patches to various parts of the tree
* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
document while_each_thread(), change first_tid() to use for_each_thread()
drivers/char/mem.c: shrink character device's devlist[] array
x86/crash: optimize CPU changes
crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
crash: hotplug support for kexec_load()
x86/crash: add x86 crash hotplug support
crash: memory and CPU hotplug sysfs attributes
kexec: exclude elfcorehdr from the segment digest
crash: add generic infrastructure for crash hotplug support
crash: move a few code bits to setup support of crash hotplug
kstrtox: consistently use _tolower()
kill do_each_thread()
nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
scripts/bloat-o-meter: count weak symbol sizes
treewide: drop CONFIG_EMBEDDED
lockdep: fix static memory detection even more
lib/vsprintf: declare no_hash_pointers in sprintf.h
lib/vsprintf: split out sprintf() and friends
kernel/fork: stop playing lockless games for exe_file replacement
adfs: delete unused "union adfs_dirtail" definition
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 cleanups from Ingo Molnar:
"The following commit deserves special mention:
22dc02f81cddd Revert "sched/fair: Move unused stub functions to header"
This is in x86/cleanups, because the revert is a re-application of a
number of cleanups that got removed inadvertedly"
[ This also effectively undoes the amd_check_microcode() microcode
declaration change I had done in my microcode loader merge in commit
42a7f6e3ffe0 ("Merge tag 'x86_microcode_for_v6.6_rc1' [...]").
I picked the declaration change by Arnd from this branch instead,
which put it in <asm/processor.h> instead of <asm/microcode.h> like I
had done in my merge resolution - Linus ]
* tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/uv: Refactor code using deprecated strncpy() interface to use strscpy()
x86/hpet: Refactor code using deprecated strncpy() interface to use strscpy()
x86/platform/uv: Refactor code using deprecated strcpy()/strncpy() interfaces to use strscpy()
x86/qspinlock-paravirt: Fix missing-prototype warning
x86/paravirt: Silence unused native_pv_lock_init() function warning
x86/alternative: Add a __alt_reloc_selftest() prototype
x86/purgatory: Include header for warn() declaration
x86/asm: Avoid unneeded __div64_32 function definition
Revert "sched/fair: Move unused stub functions to header"
x86/apic: Hide unused safe_smp_processor_id() on 32-bit UP
x86/cpu: Fix amd_check_microcode() declaration
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull RCU updates from Paul McKenney:
- Documentation updates
- Miscellaneous fixes, perhaps most notably simplifying
SRCU_NOTIFIER_INIT() as suggested
- RCU Tasks updates, most notably treating Tasks RCU callbacks as lazy
while still treating synchronous grace periods as urgent. Also fixes
one bug that restores the ability to apply debug-objects to RCU Tasks
and another that fixes a race condition that could result in
false-positive failures of the boot-time self-test code
- RCU-scalability performance-test updates, most notably adding the
ability to measure the RCU-Tasks's grace-period kthread's CPU
consumption. This proved quite useful for the RCU Tasks work
- Reference-acquisition/release performance-test updates, including a
fix for an uninitialized wait_queue_head_t
- Miscellaneous torture-test updates
- Torture-test scripting updates, including removal of the
non-longer-functional formal-verification scripts, test builds of
individual RCU Tasks flavors, better diagnostics for loss of
connectivity for distributed rcutorture tests, disabling of reboot
loops in qemu/KVM-based rcutorture testing, and passing of init
parameters to rcutorture's init program
* tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (64 commits)
rcu: Use WRITE_ONCE() for assignments to ->next for rculist_nulls
rcu: Make the rcu_nocb_poll boot parameter usable via boot config
rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load
srcu,notifier: Remove #ifdefs in favor of SRCU Tiny srcu_usage
rcutorture: Stop right-shifting torture_random() return values
torture: Stop right-shifting torture_random() return values
torture: Move stutter_wait() timeouts to hrtimers
torture: Move torture_shuffle() timeouts to hrtimers
torture: Move torture_onoff() timeouts to hrtimers
torture: Make torture_hrtimeout_*() use TASK_IDLE
torture: Add lock_torture writer_fifo module parameter
torture: Add a kthread-creation callback to _torture_create_kthread()
rcu-tasks: Fix boot-time RCU tasks debug-only deadlock
rcu-tasks: Permit use of debug-objects with RCU Tasks flavors
checkpatch: Complain about unexpected uses of RCU Tasks Trace
torture: Cause mkinitrd.sh to indicate failure on compile errors
torture: Make init program dump command-line arguments
torture: Switch qemu from -nographic to -display none
torture: Add init-program support for loongarch
torture: Avoid torture-test reboot loops
...
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On the parisc architecture, lockdep reports for all static objects which
are in the __initdata section (e.g. "setup_done" in devtmpfs,
"kthreadd_done" in init/main.c) this warning:
INFO: trying to register non-static key.
The warning itself is wrong, because those objects are in the __initdata
section, but the section itself is on parisc outside of range from
_stext to _end, which is why the static_obj() functions returns a wrong
answer.
While fixing this issue, I noticed that the whole existing check can
be simplified a lot.
Instead of checking against the _stext and _end symbols (which include
code areas too) just check for the .data and .bss segments (since we check a
data object). This can be done with the existing is_kernel_core_data()
macro.
In addition objects in the __initdata section can be checked with
init_section_contains(), and is_kernel_rodata() allows keys to be in the
_ro_after_init section.
This partly reverts and simplifies commit bac59d18c701 ("x86/setup: Fix static
memory detection").
Link: https://lkml.kernel.org/r/ZNqrLRaOi/3wPAdp@p100
Fixes: bac59d18c701 ("x86/setup: Fix static memory detection")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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