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Commit 09dc3cf9 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Linus Torvalds
Browse files

printk: avoid double lock acquire 



Commit 4f2a8d3c ("printk: Fix console_sem vs logbuf_lock unlock race")
introduced another silly bug where we would want to acquire an already
held lock.  Avoid this.

Reported-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c193c82f

kernel/printk.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -1293,10 +1293,11 @@ void console_unlock(void) 
	raw_spin_lock(&logbuf_lock);

	raw_spin_lock(&logbuf_lock);

	if (con_start != log_end)

	if (con_start != log_end)

		retry = 1;

		retry = 1;

	raw_spin_unlock_irqrestore(&logbuf_lock, flags);



	if (retry && console_trylock())

	if (retry && console_trylock())

		goto again;

		goto again;





	raw_spin_unlock_irqrestore(&logbuf_lock, flags);

	if (wake_klogd)

	if (wake_klogd)

		wake_up_klogd();

		wake_up_klogd();

}

}