[PATCH] lockdep: allow read_lock() recursion of same class
From: Ingo Molnar <mingo@elte.hu>
lockdep so far only allowed read-recursion for the same lock instance.
This is enough in the overwhelming majority of cases, but a hostap case
triggered and reported by Miles Lane relies on same-class
different-instance recursion. So we relax the restriction on read-lock
recursion.
(This change does not allow rwsem read-recursion, which is still
forbidden.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index dd05809..f32ca78 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -843,10 +843,9 @@
continue;
/*
* Allow read-after-read recursion of the same
- * lock instance (i.e. read_lock(lock)+read_lock(lock)):
+ * lock class (i.e. read_lock(lock)+read_lock(lock)):
*/
- if ((read == 2) && prev->read &&
- (prev->instance == next_instance))
+ if ((read == 2) && prev->read)
return 2;
return print_deadlock_bug(curr, prev, next);
}