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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Waiman Long <longman@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 221/663] locking/lockdep: Avoid unmatched unlock
Date:   Mon,  1 Mar 2021 17:07:49 +0100
Message-Id: <20210301161152.730348458@linuxfoundation.org>
In-Reply-To: <20210301161141.760350206@linuxfoundation.org>
References: <20210301161141.760350206@linuxfoundation.org>
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From: Peter Zijlstra <peterz@infradead.org>

[ 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@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/YBfkuyIfB1+VRxXP@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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