[PATCH 5.11 264/775] locking/lockdep: Avoid unmatched unlock

From: Greg Kroah-Hartman
Date: Mon Mar 01 2021 - 22:08:13 EST


From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

[ Upstream commit 7f82e631d236cafd28518b998c6d4d8dc2ef68f6 ]

Commit f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI"
inversions") overlooked that print_usage_bug() releases the graph_lock
and called it without the graph lock held.

Fixes: f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions")
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Waiman Long <longman@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/YBfkuyIfB1+VRxXP@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/locking/lockdep.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index bdaf4829098c0..780012eb2f3fe 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3707,7 +3707,7 @@ static void
print_usage_bug(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ if (!debug_locks_off() || debug_locks_silent)
return;

pr_warn("\n");
@@ -3748,6 +3748,7 @@ valid_state(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
{
if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) {
+ graph_unlock();
print_usage_bug(curr, this, bad_bit, new_bit);
return 0;
}
--
2.27.0