WSL2-Linux-Kernel/kernel/locking
Waiman Long 1388c10b32 locking/lockdep: Iterate lock_classes directly when reading lockdep files
[ Upstream commit fb7275acd6 ]

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>
2022-04-08 14:23:57 +02:00
..
Makefile locking/ww_mutex: Implement rtmutex based ww_mutex API functions 2021-08-17 19:05:26 +02:00
irqflag-debug.c
lock_events.c
lock_events.h
lock_events_list.h
lockdep.c locking/lockdep: Iterate lock_classes directly when reading lockdep files 2022-04-08 14:23:57 +02:00
lockdep_internals.h locking/lockdep: Iterate lock_classes directly when reading lockdep files 2022-04-08 14:23:57 +02:00
lockdep_proc.c locking/lockdep: Iterate lock_classes directly when reading lockdep files 2022-04-08 14:23:57 +02:00
lockdep_states.h
locktorture.c locktorture: Count lock readers 2021-07-27 11:39:30 -07:00
mcs_spinlock.h
mutex-debug.c locking/ww_mutex: Gather mutex_waiter initialization 2021-08-17 19:04:41 +02:00
mutex.c locking/ww_mutex: Initialize waiter.ww_ctx properly 2021-08-20 12:15:54 +02:00
mutex.h locking/mutex: Move the 'struct mutex_waiter' definition from <linux/mutex.h> to the internal header 2021-08-17 18:24:31 +02:00
osq_lock.c
percpu-rwsem.c
qrwlock.c
qspinlock.c
qspinlock_paravirt.h
qspinlock_stat.h
rtmutex.c locking/rtmutex: Fix incorrect condition in rtmutex_spin_on_owner() 2021-12-22 09:32:48 +01:00
rtmutex_api.c locking/rtmutex: Prevent lockdep false positive with PI futexes 2021-08-17 19:06:02 +02:00
rtmutex_common.h locking/rtmutex: Dont dereference waiter lockless 2021-08-25 15:42:32 +02:00
rwbase_rt.c locking/rwbase: Take care of ordering guarantee for fastpath reader 2021-09-15 17:49:16 +02:00
rwsem.c locking/rwsem: Make handoff bit handling more consistent 2021-12-01 09:04:54 +01:00
semaphore.c locking/semaphore: Add might_sleep() to down_*() family 2021-08-20 12:33:17 +02:00
spinlock.c locking/rwlock: Provide RT variant 2021-08-17 17:50:51 +02:00
spinlock_debug.c locking/rwlock: Provide RT variant 2021-08-17 17:50:51 +02:00
spinlock_rt.c locking/spinlock/rt: Prepare for RT local_lock 2021-08-17 19:06:13 +02:00
test-ww_mutex.c
ww_mutex.h locking/ww_mutex: Add rt_mutex based lock type and accessors 2021-08-17 19:05:11 +02:00
ww_rt_mutex.c locking/ww_mutex: Implement rtmutex based ww_mutex API functions 2021-08-17 19:05:26 +02:00