[PATCH] lockdep: more unlock-on-error fixes
- returns after DEBUG_LOCKS_WARN_ON added in 3 places
- debug_locks checking after lookup_chain_cache() added in
__lock_acquire()
- locking for testing and changing global variable max_lockdep_depth
added in __lock_acquire()
From: Ingo Molnar <mingo@elte.hu>
My __acquire_lock() cleanup introduced a locking bug: on SMP systems we'd
release a non-owned graph lock. Fix this by moving the graph unlock back,
and by leaving the max_lockdep_depth variable update possibly racy. (we
dont care, it's just statistics)
Also add some minimal debugging code to graph_unlock()/graph_lock(),
which caught this locking bug.
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>