| From | Luis Henriques <> | Subject | [PATCH 96/98] printk: Fix rq->lock vs logbuf_lock unlock lock inversion | Date | Thu, 11 Jul 2013 15:25:06 +0100 |
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3.5.7.17 -stable review patch. If anyone has any objections, please let me know.
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From: "Bu, Yitian" <ybu@qti.qualcomm.com>
commit dbda92d16f8655044e082930e4e9d244b87fde77 upstream.
commit 07354eb1a74d1 ("locking printk: Annotate logbuf_lock as raw") reintroduced a lock inversion problem which was fixed in commit 0b5e1c5255 ("printk: Release console_sem after logbuf_lock"). This happened probably when fixing up patch rejects.
Restore the ordering and unlock logbuf_lock before releasing console_sem.
Signed-off-by: ybu <ybu@qti.qualcomm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/E807E903FE6CBE4D95E420FBFCC273B827413C@nasanexd01h.na.qualcomm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- kernel/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/printk.c b/kernel/printk.c index 5758501..e959512 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -1330,9 +1330,9 @@ static int console_trylock_for_printk(unsigned int cpu) } } logbuf_cpu = UINT_MAX; + raw_spin_unlock(&logbuf_lock); if (wake) up(&console_sem); - raw_spin_unlock(&logbuf_lock); return retval; } -- 1.8.1.2
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