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commit c14ecb555c3ee80eeb030a4e46d00e679537f03a upstream.
KCSAN reports:
BUG: KCSAN: data-race in do_raw_write_lock / do_raw_write_lock
write (marked) to 0xffff800009cf504c of 4 bytes by task 1102 on cpu 1:
do_raw_write_lock+0x120/0x204
_raw_write_lock_irq
do_exit
call_usermodehelper_exec_async
ret_from_fork
read to 0xffff800009cf504c of 4 bytes by task 1103 on cpu 0:
do_raw_write_lock+0x88/0x204
_raw_write_lock_irq
do_exit
call_usermodehelper_exec_async
ret_from_fork
value changed: 0xffffffff -> 0x00000001
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1103 Comm: kworker/u4:1 6.1.111
Commit 1a365e822372 ("locking/spinlock/debug: Fix various data races") has
adressed most of these races, but seems to be not consistent/not complete.
>From do_raw_write_lock() only debug_write_lock_after() part has been
converted to WRITE_ONCE(), but not debug_write_lock_before() part.
Do it now.
Fixes: 1a365e822372 ("locking/spinlock/debug: Fix various data races")
Reported-by: Adrian Freihofer <adrian.freihofer@siemens.com>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 495f53d5cca0f939eaed9dca90b67e7e6fb0e30c upstream.
Currently, when a lock class is allocated, nr_unused_locks will be
increased by 1, until it gets used: nr_unused_locks will be decreased by
1 in mark_lock(). However, one scenario is missed: a lock class may be
zapped without even being used once. This could result into a situation
that nr_unused_locks != 0 but no unused lock class is active in the
system, and when `cat /proc/lockdep_stats`, a WARN_ON() will
be triggered in a CONFIG_DEBUG_LOCKDEP=y kernel:
[...] DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused)
[...] WARNING: CPU: 41 PID: 1121 at kernel/locking/lockdep_proc.c:283 lockdep_stats_show+0xba9/0xbd0
And as a result, lockdep will be disabled after this.
Therefore, nr_unused_locks needs to be accounted correctly at
zap_class() time.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250326180831.510348-1-boqun.feng@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 85b2b9c16d053364e2004883140538e73b333cdb ]
A circular lock dependency splat has been seen involving down_trylock():
======================================================
WARNING: possible circular locking dependency detected
6.12.0-41.el10.s390x+debug
------------------------------------------------------
dd/32479 is trying to acquire lock:
0015a20accd0d4f8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x26/0x90
but task is already holding lock:
000000017e461698 (&zone->lock){-.-.}-{2:2}, at: rmqueue_bulk+0xac/0x8f0
the existing dependency chain (in reverse order) is:
-> #4 (&zone->lock){-.-.}-{2:2}:
-> #3 (hrtimer_bases.lock){-.-.}-{2:2}:
-> #2 (&rq->__lock){-.-.}-{2:2}:
-> #1 (&p->pi_lock){-.-.}-{2:2}:
-> #0 ((console_sem).lock){-.-.}-{2:2}:
The console_sem -> pi_lock dependency is due to calling try_to_wake_up()
while holding the console_sem raw_spinlock. This dependency can be broken
by using wake_q to do the wakeup instead of calling try_to_wake_up()
under the console_sem lock. This will also make the semaphore's
raw_spinlock become a terminal lock without taking any further locks
underneath it.
The hrtimer_bases.lock is a raw_spinlock while zone->lock is a
spinlock. The hrtimer_bases.lock -> zone->lock dependency happens via
the debug_objects_fill_pool() helper function in the debugobjects code.
-> #4 (&zone->lock){-.-.}-{2:2}:
__lock_acquire+0xe86/0x1cc0
lock_acquire.part.0+0x258/0x630
lock_acquire+0xb8/0xe0
_raw_spin_lock_irqsave+0xb4/0x120
rmqueue_bulk+0xac/0x8f0
__rmqueue_pcplist+0x580/0x830
rmqueue_pcplist+0xfc/0x470
rmqueue.isra.0+0xdec/0x11b0
get_page_from_freelist+0x2ee/0xeb0
__alloc_pages_noprof+0x2c2/0x520
alloc_pages_mpol_noprof+0x1fc/0x4d0
alloc_pages_noprof+0x8c/0xe0
allocate_slab+0x320/0x460
___slab_alloc+0xa58/0x12b0
__slab_alloc.isra.0+0x42/0x60
kmem_cache_alloc_noprof+0x304/0x350
fill_pool+0xf6/0x450
debug_object_activate+0xfe/0x360
enqueue_hrtimer+0x34/0x190
__run_hrtimer+0x3c8/0x4c0
__hrtimer_run_queues+0x1b2/0x260
hrtimer_interrupt+0x316/0x760
do_IRQ+0x9a/0xe0
do_irq_async+0xf6/0x160
Normally a raw_spinlock to spinlock dependency is not legitimate
and will be warned if CONFIG_PROVE_RAW_LOCK_NESTING is enabled,
but debug_objects_fill_pool() is an exception as it explicitly
allows this dependency for non-PREEMPT_RT kernel without causing
PROVE_RAW_LOCK_NESTING lockdep splat. As a result, this dependency is
legitimate and not a bug.
Anyway, semaphore is the only locking primitive left that is still
using try_to_wake_up() to do wakeup inside critical section, all the
other locking primitives had been migrated to use wake_q to do wakeup
outside of the critical section. It is also possible that there are
other circular locking dependencies involving printk/console_sem or
other existing/new semaphores lurking somewhere which may show up in
the future. Let just do the migration now to wake_q to avoid headache
like this.
Reported-by: yzbot+ed801a886dfdbfe7136d@syzkaller.appspotmail.com
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250307232717.1759087-3-boqun.feng@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit a6f88ac32c6e63e69c595bfae220d8641704c9b7 upstream.
There is a deadlock scenario between lockdep and rcu when
rcu nocb feature is enabled, just as following call stack:
rcuop/x
-000|queued_spin_lock_slowpath(lock = 0xFFFFFF817F2A8A80, val = ?)
-001|queued_spin_lock(inline) // try to hold nocb_gp_lock
-001|do_raw_spin_lock(lock = 0xFFFFFF817F2A8A80)
-002|__raw_spin_lock_irqsave(inline)
-002|_raw_spin_lock_irqsave(lock = 0xFFFFFF817F2A8A80)
-003|wake_nocb_gp_defer(inline)
-003|__call_rcu_nocb_wake(rdp = 0xFFFFFF817F30B680)
-004|__call_rcu_common(inline)
-004|call_rcu(head = 0xFFFFFFC082EECC28, func = ?)
-005|call_rcu_zapped(inline)
-005|free_zapped_rcu(ch = ?)// hold graph lock
-006|rcu_do_batch(rdp = 0xFFFFFF817F245680)
-007|nocb_cb_wait(inline)
-007|rcu_nocb_cb_kthread(arg = 0xFFFFFF817F245680)
-008|kthread(_create = 0xFFFFFF80803122C0)
-009|ret_from_fork(asm)
rcuop/y
-000|queued_spin_lock_slowpath(lock = 0xFFFFFFC08291BBC8, val = 0)
-001|queued_spin_lock()
-001|lockdep_lock()
-001|graph_lock() // try to hold graph lock
-002|lookup_chain_cache_add()
-002|validate_chain()
-003|lock_acquire
-004|_raw_spin_lock_irqsave(lock = 0xFFFFFF817F211D80)
-005|lock_timer_base(inline)
-006|mod_timer(inline)
-006|wake_nocb_gp_defer(inline)// hold nocb_gp_lock
-006|__call_rcu_nocb_wake(rdp = 0xFFFFFF817F2A8680)
-007|__call_rcu_common(inline)
-007|call_rcu(head = 0xFFFFFFC0822E0B58, func = ?)
-008|call_rcu_hurry(inline)
-008|rcu_sync_call(inline)
-008|rcu_sync_func(rhp = 0xFFFFFFC0822E0B58)
-009|rcu_do_batch(rdp = 0xFFFFFF817F266680)
-010|nocb_cb_wait(inline)
-010|rcu_nocb_cb_kthread(arg = 0xFFFFFF817F266680)
-011|kthread(_create = 0xFFFFFF8080363740)
-012|ret_from_fork(asm)
rcuop/x and rcuop/y are rcu nocb threads with the same nocb gp thread.
This patch release the graph lock before lockdep call_rcu.
Fixes: a0b0fd53e1e6 ("locking/lockdep: Free lock classes that are no longer in use")
Cc: stable@vger.kernel.org
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240620225436.3127927-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d33d26036a0274b472299d7dcdaa5fb34329f91b upstream.
rt_mutex_handle_deadlock() is called with rt_mutex::wait_lock held. In the
good case it returns with the lock held and in the deadlock case it emits a
warning and goes into an endless scheduling loop with the lock held, which
triggers the 'scheduling in atomic' warning.
Unlock rt_mutex::wait_lock in the dead lock case before issuing the warning
and dropping into the schedule for ever loop.
[ tglx: Moved unlock before the WARN(), removed the pointless comment,
massaged changelog, added Fixes tag ]
Fixes: 3d5c9340d194 ("rtmutex: Handle deadlock detection smarter")
Signed-off-by: Roland Xu <mu001999@outlook.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/ME0P300MB063599BEF0743B8FA339C2CECC802@ME0P300MB0635.AUSP300.PROD.OUTLOOK.COM
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit bca4104b00fec60be330cd32818dd5c70db3d469 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit bccdd808902f8c677317cec47c306e42b93b849e ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit eae6d58d67d9739be5f7ae2dbead1d0ef6528243 ]
Commit dfd5e3f5fe27 ("locking/lockdep: Mark local_lock_t") added yet
another lockdep_init_map_*() variant, but forgot to update all the
existing users of the most complicated version.
This could lead to a loss of lock_type and hence an incorrect report.
Given the relative rarity of both local_lock and these annotations,
this is unlikely to happen in practise, still, best fix things.
Fixes: dfd5e3f5fe27 ("locking/lockdep: Mark local_lock_t")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YqyEDtoan20K0CVD@worktop.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 5dc33592e95534dc8455ce3e9baaaf3dae0fff82 upstream.
Since syzkaller continues various test cases until the kernel crashes,
syzkaller tends to examine more locking dependencies than normal systems.
As a result, syzbot is reporting that the fuzz testing was terminated
due to hitting upper limits lockdep can track [1] [2] [3]. Since analysis
via /proc/lockdep* did not show any obvious culprit [4] [5], we have no
choice but allow tuning tracing capacity constants.
[1] https://syzkaller.appspot.com/bug?id=3d97ba93fb3566000c1c59691ea427370d33ea1b
[2] https://syzkaller.appspot.com/bug?id=381cb436fe60dc03d7fd2a092b46d7f09542a72a
[3] https://syzkaller.appspot.com/bug?id=a588183ac34c1437fc0785e8f220e88282e5a29f
[4] https://lkml.kernel.org/r/4b8f7a57-fa20-47bd-48a0-ae35d860f233@i-love.sakura.ne.jp
[5] https://lkml.kernel.org/r/1c351187-253b-2d49-acaf-4563c63ae7d2@i-love.sakura.ne.jp
References: https://lkml.kernel.org/r/1595640639-9310-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit fb7275acd6fb988313dddd8d3d19efa70d9015ad ]
When dumping lock_classes information via /proc/lockdep, we can't take
the lockdep lock as the lock hold time is indeterminate. Iterating
over all_lock_classes without holding lock can be dangerous as there
is a slight chance that it may branch off to other lists leading to
infinite loop or even access invalid memory if changes are made to
all_lock_classes list in parallel.
To avoid this problem, iteration of lock classes is now done directly
on the lock_classes array itself. The lock_classes_in_use bitmap is
checked to see if the lock class is being used. To avoid iterating
the full array all the times, a new max_lock_class_idx value is added
to track the maximum lock_class index that is currently being used.
We can theoretically take the lockdep lock for iterating all_lock_classes
when other lockdep files (lockdep_stats and lock_stat) are accessed as
the lock hold time will be shorter for them. For consistency, they are
also modified to iterate the lock_classes array directly.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220211035526.1329503-2-longman@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 61cc4534b6550997c97a03759ab46b29d44c0017 upstream.
It was found that reading /proc/lockdep after a lockdep splat may
potentially cause an access to freed memory if lockdep_unregister_key()
is called after the splat but before access to /proc/lockdep [1]. This
is due to the fact that graph_lock() call in lockdep_unregister_key()
fails after the clearing of debug_locks by the splat process.
After lockdep_unregister_key() is called, the lock_name may be freed
but the corresponding lock_class structure still have a reference to
it. That invalid memory pointer will then be accessed when /proc/lockdep
is read by a user and a use-after-free (UAF) error will be reported if
KASAN is enabled.
To fix this problem, lockdep_unregister_key() is now modified to always
search for a matching key irrespective of the debug_locks state and
zap the corresponding lock class if a matching one is found.
[1] https://lore.kernel.org/lkml/77f05c15-81b6-bddd-9650-80d5f23fe330@i-love.sakura.ne.jp/
Fixes: 8b39adbee805 ("locking/lockdep: Make lockdep_unregister_key() honor 'debug_locks' again")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Cc: Cheng-Jui Wang <cheng-jui.wang@mediatek.com>
Link: https://lkml.kernel.org/r/20220103023558.1377055-1-longman@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 28df029d53a2fd80c1b8674d47895648ad26dcfb upstream.
A kernel exception was hit when trying to dump /proc/lockdep_chains after
lockdep report "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!":
Unable to handle kernel paging request at virtual address 00054005450e05c3
...
00054005450e05c3] address between user and kernel address ranges
...
pc : [0xffffffece769b3a8] string+0x50/0x10c
lr : [0xffffffece769ac88] vsnprintf+0x468/0x69c
...
Call trace:
string+0x50/0x10c
vsnprintf+0x468/0x69c
seq_printf+0x8c/0xd8
print_name+0x64/0xf4
lc_show+0xb8/0x128
seq_read_iter+0x3cc/0x5fc
proc_reg_read_iter+0xdc/0x1d4
The cause of the problem is the function lock_chain_get_class() will
shift lock_classes index by 1, but the index don't need to be shifted
anymore since commit 01bb6f0af992 ("locking/lockdep: Change the range
of class_idx in held_lock struct") already change the index to start
from 0.
The lock_classes[-1] located at chain_hlocks array. When printing
lock_classes[-1] after the chain_hlocks entries are modified, the
exception happened.
The output of lockdep_chains are incorrect due to this problem too.
Fixes: f611e8cf98ec ("lockdep: Take read/write status in consideration when generate chainkey")
Signed-off-by: Cheng Jui Wang <cheng-jui.wang@mediatek.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20220210105011.21712-1-cheng-jui.wang@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit c034f48e99907d5be147ac8f0f3e630a9307c2be ]
Drop repeated words in kernel/events/.
{if, the, that, with, time}
Drop repeated words in kernel/locking/.
{it, no, the}
Drop repeated words in kernel/sched/.
{in, not}
Link: https://lkml.kernel.org/r/20210127023412.26292-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Will Deacon <will@kernel.org> [kernel/locking/]
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 2507003a1d10917c9158077bf6030719d02c941e ]
lock_is_held_type(, 1) detects acquired read locks. It only recognized
locks acquired with lock_acquire_shared(). Read locks acquired with
lock_acquire_shared_recursive() are not recognized because a `2' is
stored as the read value.
Rework the check to additionally recognise lock's read value one and two
as a read held lock.
Fixes: e918188611f07 ("locking: More accurate annotations for read_lock()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20210903084001.lblecrvz4esl4mrr@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit ce0b9c805dd66d5e49fd53ec5415ae398f4c56e6 ]
vmlinux.o: warning: objtool: look_up_lock_class()+0xc7: call to rcu_read_lock_any_held() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210624095148.311980536@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit dfd5e3f5fe27bda91d5cc028c86ffbb7a0614489 ]
The local_lock_t's are special, because they cannot form IRQ
inversions, make sure we can tell them apart from the rest of the
locks.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 048661a1f963e9517630f080687d48af79ed784c ]
Yanfei reported that setting HANDOFF should not depend on recomputing
@first, only on @first state. Which would then give:
if (ww_ctx || !first)
first = __mutex_waiter_is_first(lock, &waiter);
if (first)
__mutex_set_flag(lock, MUTEX_FLAG_HANDOFF);
But because 'ww_ctx || !first' is basically 'always' and the test for
first is relatively cheap, omit that first branch entirely.
Reported-by: Yanfei Xu <yanfei.xu@windriver.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Yanfei Xu <yanfei.xu@windriver.com>
Link: https://lore.kernel.org/r/20210630154114.896786297@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f8b298cc39f0619544c607eaef09fd0b2afd10f3 ]
Even the very first lock can violate the wait-context check, consider
the various IRQ contexts.
Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20210617190313.256987481@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7b1f8c6179769af6ffa055e1169610b51d71edd5 ]
In the step #3 of check_irq_usage(), we seach backwards to find a lock
whose usage conflicts the usage of @target_entry1 on safe/unsafe.
However, we should only keep the irq-unsafe usage of @target_entry1 into
consideration, because it could be a case where a lock is hardirq-unsafe
but soft-safe, and in check_irq_usage() we find it because its
hardirq-unsafe could result into a hardirq-safe-unsafe deadlock, but
currently since we don't filter out the other usage bits, so we may find
a lock dependency path softirq-unsafe -> softirq-safe, which in fact
doesn't cause a deadlock. And this may cause misleading lockdep splats.
Fix this by only keeping LOCKF_ENABLED_IRQ_ALL bits when we try the
backwards search.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210618170110.3699115-4-boqun.feng@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 69c7a5fb2482636f525f016c8333fdb9111ecb9d ]
We use the same code to print backwards lock dependency path as the
forwards lock dependency path, and this could result into incorrect
printing because for a backwards lock_list ->trace is not the call trace
where the lock of ->class is acquired.
Fix this by introducing a separate function on printing the backwards
dependency path. Also add a few comments about the printing while we are
at it.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210618170110.3699115-2-boqun.feng@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 49faa77759b211fff344898edc23bb780707fff5 ]
Better handle the failure paths.
vmlinux.o: warning: objtool: debug_locks_off()+0x23: call to console_verbose() leaves .noinstr.text section
vmlinux.o: warning: objtool: debug_locks_off()+0x19: call to __kasan_check_write() leaves .noinstr.text section
debug_locks_off+0x19/0x40:
instrument_atomic_write at include/linux/instrumented.h:86
(inlined by) __debug_locks_off at include/linux/debug_locks.h:17
(inlined by) debug_locks_off at lib/debug_locks.c:41
Fixes: 6eebad1ad303 ("lockdep: __always_inline more for noinstr")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210621120120.784404944@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3a010c493271f04578b133de977e0e5dd2848cea ]
When a interruptible mutex locker is interrupted by a signal
without acquiring this lock and removed from the wait queue.
if the mutex isn't contended enough to have a waiter
put into the wait queue again, the setting of the WAITER
bit will force mutex locker to go into the slowpath to
acquire the lock every time, so if the wait queue is empty,
the WAITER bit need to be clear.
Fixes: 040a0a371005 ("mutex: Add support for wound/wait style locks")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210517034005.30828-1-qiang.zhang@windriver.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 89e70d5c583c55088faa2201d397ee30a15704aa ]
The commit eb1f00237aca ("lockdep,trace: Expose tracepoints") reverses
tracepoints for lock_contended() and lock_acquired(), thus the ftrace
log shows the wrong locking sequence that "acquired" event is prior to
"contended" event:
<idle>-0 [001] d.s3 20803.501685: lock_acquire: 0000000008b91ab4 &sg_policy->update_lock
<idle>-0 [001] d.s3 20803.501686: lock_acquired: 0000000008b91ab4 &sg_policy->update_lock
<idle>-0 [001] d.s3 20803.501689: lock_contended: 0000000008b91ab4 &sg_policy->update_lock
<idle>-0 [001] d.s3 20803.501690: lock_release: 0000000008b91ab4 &sg_policy->update_lock
This patch fixes calling tracepoints for lock_contended() and
lock_acquired().
Fixes: eb1f00237aca ("lockdep,trace: Expose tracepoints")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210512120937.90211-1-leo.yan@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 84a24bf8c52e66b7ac89ada5e3cfbe72d65c1896 ]
While this code is executed with the wait_lock held, a reader can
acquire the lock without holding wait_lock. The writer side loops
checking the value with the atomic_cond_read_acquire(), but only truly
acquires the lock when the compare-and-exchange is completed
successfully which isn’t ordered. This exposes the window between the
acquire and the cmpxchg to an A-B-A problem which allows reads
following the lock acquisition to observe values speculatively before
the write lock is truly acquired.
We've seen a problem in epoll where the reader does a xchg while
holding the read lock, but the writer can see a value change out from
under it.
Writer | Reader
--------------------------------------------------------------------------------
ep_scan_ready_list() |
|- write_lock_irq() |
|- queued_write_lock_slowpath() |
|- atomic_cond_read_acquire() |
| read_lock_irqsave(&ep->lock, flags);
--> (observes value before unlock) | chain_epi_lockless()
| | epi->next = xchg(&ep->ovflist, epi);
| | read_unlock_irqrestore(&ep->lock, flags);
| |
| atomic_cmpxchg_relaxed() |
|-- READ_ONCE(ep->ovflist); |
A core can order the read of the ovflist ahead of the
atomic_cmpxchg_relaxed(). Switching the cmpxchg to use acquire
semantics addresses this issue at which point the atomic_cond_read can
be switched to use relaxed semantics.
Fixes: b519b56e378ee ("locking/qrwlock: Use atomic_cond_read_acquire() when spinning in qrwlock")
Signed-off-by: Ali Saidi <alisaidi@amazon.com>
[peterz: use try_cmpxchg()]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Tested-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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non-static key" message
[ Upstream commit 3a85969e9d912d5dd85362ee37b5f81266e00e77 ]
Since this message is printed when dynamically allocated spinlocks (e.g.
kzalloc()) are used without initialization (e.g. spin_lock_init()),
suggest to developers to check whether initialization functions for objects
were called, before making developers wonder what annotation is missing.
[ mingo: Minor tweaks to the message. ]
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210321064913.4619-1-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 6d48b7912cc72275dc7c59ff961c8bac7ef66a92 upstream.
Clang doesn't like format strings that truncate a 32-bit
value to something shorter:
kernel/locking/lockdep.c:709:4: error: format specifies type 'short' but the argument has type 'int' [-Werror,-Wformat]
In this case, the warning is a slightly questionable, as it could realize
that both class->wait_type_outer and class->wait_type_inner are in fact
8-bit struct members, even though the result of the ?: operator becomes an
'int'.
However, there is really no point in printing the number as a 16-bit
'short' rather than either an 8-bit or 32-bit number, so just change
it to a normal %d.
Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210322115531.3987555-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5de2055d31ea88fd9ae9709ac95c372a505a60fa ]
The use_ww_ctx flag is passed to mutex_optimistic_spin(), but the
function doesn't use it. The frequent use of the (use_ww_ctx && ww_ctx)
combination is repetitive.
In fact, ww_ctx should not be used at all if !use_ww_ctx. Simplify
ww_mutex code by dropping use_ww_ctx from mutex_optimistic_spin() an
clear ww_ctx if !use_ww_ctx. In this way, we can replace (use_ww_ctx &&
ww_ctx) by just (ww_ctx).
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210316153119.13802-2-longman@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7f82e631d236cafd28518b998c6d4d8dc2ef68f6 ]
Commit f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI"
inversions") overlooked that print_usage_bug() releases the graph_lock
and called it without the graph lock held.
Fixes: f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/YBfkuyIfB1+VRxXP@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 77ca93a6b1223e210e58e1000c09d8d420403c94 ]
vmlinux.o: warning: objtool: lock_is_held_type()+0x60: call to check_flags.part.0() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210106144017.652218215@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 2156ac1934166d6deb6cd0f6ffc4c1076ec63697 upstream
Nothing uses the argument. Remove it as preparation to use
pi_state_update_owner().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0afda3a888dccf12557b41ef42eee942327d122b upstream.
When the compiler doesn't feel like inlining, it causes a noinstr
fail:
vmlinux.o: warning: objtool: lock_is_held_type()+0xb: call to lockdep_enabled() leaves .noinstr.text section
Fixes: 4d004099a668 ("lockdep: Fix lockdep recursion")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210106144017.592595176@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 31784cff7ee073b34d6eddabb95e3be2880a425c ]
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_interruptible. This is needed for perf_event_open to be
converted (with no semantic changes) from working on a mutex to
wroking on a rwsem.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87k0tybqfy.fsf@x220.int.ebiederm.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0f9368b5bf6db0c04afc5454b1be79022a681615 ]
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_killable_nested. This is needed so that kcmp_lock
can be converted from working on a mutexes to working on rw_semaphores.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87o8jabqh3.fsf@x220.int.ebiederm.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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A warning was hit when running xfstests/generic/068 in a Hyper-V guest:
[...] ------------[ cut here ]------------
[...] DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())
[...] WARNING: CPU: 2 PID: 1350 at kernel/locking/lockdep.c:5280 check_flags.part.0+0x165/0x170
[...] ...
[...] Workqueue: events pwq_unbound_release_workfn
[...] RIP: 0010:check_flags.part.0+0x165/0x170
[...] ...
[...] Call Trace:
[...] lock_is_held_type+0x72/0x150
[...] ? lock_acquire+0x16e/0x4a0
[...] rcu_read_lock_sched_held+0x3f/0x80
[...] __send_ipi_one+0x14d/0x1b0
[...] hv_send_ipi+0x12/0x30
[...] __pv_queued_spin_unlock_slowpath+0xd1/0x110
[...] __raw_callee_save___pv_queued_spin_unlock_slowpath+0x11/0x20
[...] .slowpath+0x9/0xe
[...] lockdep_unregister_key+0x128/0x180
[...] pwq_unbound_release_workfn+0xbb/0xf0
[...] process_one_work+0x227/0x5c0
[...] worker_thread+0x55/0x3c0
[...] ? process_one_work+0x5c0/0x5c0
[...] kthread+0x153/0x170
[...] ? __kthread_bind_mask+0x60/0x60
[...] ret_from_fork+0x1f/0x30
The cause of the problem is we have call chain lockdep_unregister_key()
-> <irq disabled by raw_local_irq_save()> lockdep_unlock() ->
arch_spin_unlock() -> __pv_queued_spin_unlock_slowpath() -> pv_kick() ->
__send_ipi_one() -> trace_hyperv_send_ipi_one().
Although this particular warning is triggered because Hyper-V has a
trace point in ipi sending, but in general arch_spin_unlock() may call
another function having a trace point in it, so put the arch_spin_lock()
and arch_spin_unlock() after lock_recursion protection to fix this
problem and avoid similiar problems.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201113110512.1056501-1-boqun.feng@gmail.com
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Chris Wilson reported a problem spotted by check_chain_key(): a chain
key got changed in validate_chain() because we modify the ->read in
validate_chain() to skip checks for dependency adding, and ->read is
taken into calculation for chain key since commit f611e8cf98ec
("lockdep: Take read/write status in consideration when generate
chainkey").
Fix this by avoiding to modify ->read in validate_chain() based on two
facts: a) since we now support recursive read lock detection, there is
no need to skip checks for dependency adding for recursive readers, b)
since we have a), there is only one case left (nest_lock) where we want
to skip checks in validate_chain(), we simply remove the modification
for ->read and rely on the return value of check_deadlock() to skip the
dependency adding.
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201102053743.450459-1-boqun.feng@gmail.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"A couple of locking fixes:
- Fix incorrect failure injection handling in the fuxtex code
- Prevent a preemption warning in lockdep when tracking
local_irq_enable() and interrupts are already enabled
- Remove more raw_cpu_read() usage from lockdep which causes state
corruption on !X86 architectures.
- Make the nr_unused_locks accounting in lockdep correct again"
* tag 'locking-urgent-2020-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep: Fix nr_unused_locks accounting
locking/lockdep: Remove more raw_cpu_read() usage
futex: Fix incorrect should_fail_futex() handling
lockdep: Fix preemption WARN for spurious IRQ-enable
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Chris reported that commit 24d5a3bffef1 ("lockdep: Fix
usage_traceoverflow") breaks the nr_unused_locks validation code
triggered by /proc/lockdep_stats.
By fully splitting LOCK_USED and LOCK_USED_READ it becomes a bad
indicator for accounting nr_unused_locks; simplyfy by using any first
bit.
Fixes: 24d5a3bffef1 ("lockdep: Fix usage_traceoverflow")
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://lkml.kernel.org/r/20201027124834.GL2628@hirez.programming.kicks-ass.net
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I initially thought raw_cpu_read() was OK, since if it is !0 we have
IRQs disabled and can't get migrated, so if we get migrated both CPUs
must have 0 and it doesn't matter which 0 we read.
And while that is true; it isn't the whole store, on pretty much all
architectures (except x86) this can result in computing the address for
one CPU, getting migrated, the old CPU continuing execution with another
task (possibly setting recursion) and then the new CPU reading the value
of the old CPU, which is no longer 0.
Similer to:
baffd723e44d ("lockdep: Revert "lockdep: Use raw_cpu_*() for per-cpu variables"")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201026152256.GB2651@hirez.programming.kicks-ass.net
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It is valid (albeit uncommon) to call local_irq_enable() without first
having called local_irq_disable(). In this case we enter
lockdep_hardirqs_on*() with IRQs enabled and trip a preemption warning
for using __this_cpu_read().
Use this_cpu_read() instead to avoid the warning.
Fixes: 4d004099a6 ("lockdep: Fix lockdep recursion")
Reported-by: syzbot+53f8ce8bbc07924b6417@syzkaller.appspotmail.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU changes from Ingo Molnar:
- Debugging for smp_call_function()
- RT raw/non-raw lock ordering fixes
- Strict grace periods for KASAN
- New smp_call_function() torture test
- Torture-test updates
- Documentation updates
- Miscellaneous fixes
[ This doesn't actually pull the tag - I've dropped the last merge from
the RCU branch due to questions about the series. - Linus ]
* tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
smp: Make symbol 'csd_bug_count' static
kernel/smp: Provide CSD lock timeout diagnostics
smp: Add source and destination CPUs to __call_single_data
rcu: Shrink each possible cpu krcp
rcu/segcblist: Prevent useless GP start if no CBs to accelerate
torture: Add gdb support
rcutorture: Allow pointer leaks to test diagnostic code
rcutorture: Hoist OOM registry up one level
refperf: Avoid null pointer dereference when buf fails to allocate
rcutorture: Properly synchronize with OOM notifier
rcutorture: Properly set rcu_fwds for OOM handling
torture: Add kvm.sh --help and update help message
rcutorture: Add CONFIG_PROVE_RCU_LIST to TREE05
torture: Update initrd documentation
rcutorture: Replace HTTP links with HTTPS ones
locktorture: Make function torture_percpu_rws |
