Subject: [PATCH] lockdep: Let lock_is_held_type() detect recursive read as read
From: Sebastian Andrzej Siewior <[email-masked]>
Date: Fri, 3 Sep 2021 10:40:01 +0200

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 <[email-masked]>
Signed-off-by: Peter Zijlstra (Intel) <[email-masked]>
Acked-by: Boqun Feng <[email-masked]>
Acked-by: Waiman Long <[email-masked]>
Link: https://lkml.kernel.org/r/[email-masked]
---
 kernel/locking/lockdep.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -5366,7 +5366,7 @@ int __lock_is_held(const struct lockdep_
 		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;