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| author |   Bart Van Assche <bvanassche@acm.org> | 2018-12-06 17:11:36 -0800 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2018-12-11 14:54:55 +0100 |
| commit | 786fa29e9cb6810e21ab0d9c41a81d81d54d1d1b (patch) | |
| tree | a948ade4dca4cfed128bdeb67ee62253ee152e57 /kernel/locking | |
| parent | locking/lockdep: Remove a superfluous INIT_LIST_HEAD() statement (diff) | |
| download | linux-dev-786fa29e9cb6810e21ab0d9c41a81d81d54d1d1b.tar.xz linux-dev-786fa29e9cb6810e21ab0d9c41a81d81d54d1d1b.zip | |
locking/lockdep: Make concurrent lockdep_reset_lock() calls safe
Since zap_class() removes items from the all_lock_classes list and the
classhash_table, protect all zap_class() calls against concurrent
data structure modifications with the graph lock.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20181207011148.251812-13-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 346b5a1fd062..737d2dd3ea56 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4122,6 +4122,9 @@ void lockdep_reset(void) raw_local_irq_restore(flags); } +/* + * Remove all references to a lock class. The caller must hold the graph lock. + */ static void zap_class(struct lock_class *class) { int i; @@ -4229,6 +4232,7 @@ void lockdep_reset_lock(struct lockdep_map *lock) int j, locked; raw_local_irq_save(flags); + locked = graph_lock(); /* * Remove all classes this lock might have: @@ -4245,7 +4249,6 @@ void lockdep_reset_lock(struct lockdep_map *lock) * Debug check: in the end all mapped classes should * be gone. */ - locked = graph_lock(); if (unlikely(lock_class_cache_is_registered(lock))) { if (debug_locks_off_graph_unlock()) { /* |