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authorBart Van Assche <bvanassche@acm.org>2018-12-06 17:11:36 -0800
committerIngo Molnar <mingo@kernel.org>2018-12-11 14:54:55 +0100
commit786fa29e9cb6810e21ab0d9c41a81d81d54d1d1b (patch)
treea948ade4dca4cfed128bdeb67ee62253ee152e57 /kernel
parenta66b6922dc6a5ece60ea9326153da3b062977a4d (diff)
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')
-rw-r--r--kernel/locking/lockdep.c5
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()) {
/*