Commit-ID: 786fa29e9cb6810e21ab0d9c41a81d81d54d1d1b Gitweb: https://git.kernel.org/tip/786fa29e9cb6810e21ab0d9c41a81d81d54d1d1b Author: Bart Van Assche <bvanass...@acm.org> AuthorDate: Thu, 6 Dec 2018 17:11:36 -0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 11 Dec 2018 14:54:55 +0100
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 <bvanass...@acm.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Johannes Berg <johan...@sipsolutions.net> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Sasha Levin <sasha.le...@oracle.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Waiman Long <long...@redhat.com> Cc: johannes.b...@intel.com Cc: t...@kernel.org Link: https://lkml.kernel.org/r/20181207011148.251812-13-bvanass...@acm.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/locking/lockdep.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) 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()) { /*
