Commit 7fb4a2ce authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

locking/lockdep: Add nest_lock integrity test

Boqun reported that hlock->references can overflow. Add a debug test
for that to generate a clear error when this happens.

Without this, lockdep is likely to report a mysterious failure on
unlock.
Reported-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolai Hähnle <Nicolai.Haehnle@amd.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2b232e0c
...@@ -3260,10 +3260,17 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, ...@@ -3260,10 +3260,17 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (depth) { if (depth) {
hlock = curr->held_locks + depth - 1; hlock = curr->held_locks + depth - 1;
if (hlock->class_idx == class_idx && nest_lock) { if (hlock->class_idx == class_idx && nest_lock) {
if (hlock->references) if (hlock->references) {
/*
* Check: unsigned int references:12, overflow.
*/
if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1))
return 0;
hlock->references++; hlock->references++;
else } else {
hlock->references = 2; hlock->references = 2;
}
return 1; return 1;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment