[PATCH v3] lockdep: Let lock_is_held_type() detect recursive read as read

From: Sebastian Andrzej Siewior
Date: Fri Sep 10 2021 - 09:53:20 EST


lock_is_held_type(, 1) detects acquired read locks. It only recognized
locks acquired with lock_acquire_shared(). Read locks acquired with
lock_acquire_shared_recursive() are not recognized because a `2' is
stored as the read value.

Rework the check to additionally recognise lock's read value one and two
as a read held lock.

Fixes: e918188611f07 ("locking: More accurate annotations for read_lock()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Waiman Long <longman@xxxxxxxxxx>
Acked-by: Boqun Feng <boqun.feng@xxxxxxxxx>
---
v3: move the !! to the right spot so it actually works.

kernel/locking/lockdep.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index bf1c00c881e48..bfa0a347f27c4 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -5366,7 +5366,7 @@ int __lock_is_held(const struct lockdep_map *lock, int read)
struct held_lock *hlock = curr->held_locks + i;

if (match_held_lock(hlock, lock)) {
- if (read == -1 || hlock->read == read)
+ if (read == -1 || !!hlock->read == read)
return LOCK_STATE_HELD;

return LOCK_STATE_NOT_HELD;
--
2.33.0