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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Waiman Long <llong@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH v2] lockdep: Let lock_is_held_type() detect recursive read as read
Date: Fri, 3 Sep 2021 10:40:01 +0200	[thread overview]
Message-ID: <20210903084001.lblecrvz4esl4mrr@linutronix.de> (raw)
In-Reply-To: <9af2b074-9fcf-5aea-f37d-9b2482146489@redhat.com>

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@linutronix.de>
---
v1…v2:
  - simplify the read check to !!read as suggested by Waiman Long.

 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;

  reply	other threads:[~2021-09-03  8:40 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01 16:22 [PATCH] lockdep: Let lock_is_held_type() detect recursive read as read Sebastian Andrzej Siewior
2021-09-01 16:43 ` Boqun Feng
2021-09-03 10:45   ` Sebastian Andrzej Siewior
2021-09-03 14:15     ` Boqun Feng
2021-09-03 14:30       ` Sebastian Andrzej Siewior
2021-09-01 18:32 ` Waiman Long
2021-09-03  8:40   ` Sebastian Andrzej Siewior [this message]
2021-09-08  2:16     ` [PATCH v2] " Boqun Feng
2021-09-08 10:17       ` Peter Zijlstra
2021-09-10 13:53         ` [PATCH v3] " Sebastian Andrzej Siewior
2021-09-08 14:40       ` [PATCH v2] " Waiman Long
2021-09-08 14:35     ` Waiman Long
2021-09-17 13:17     ` [tip: locking/core] " tip-bot2 for Sebastian Andrzej Siewior

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