[tip:core/printk] printk: Fix rq->lock vs logbuf_lock unlock lock inversion

From: tip-bot for Bu, Yitian
Date: Mon Feb 18 2013 - 09:19:13 EST

Commit-ID: dbda92d16f8655044e082930e4e9d244b87fde77
Gitweb: http://git.kernel.org/tip/dbda92d16f8655044e082930e4e9d244b87fde77
Author: Bu, Yitian <ybu@xxxxxxxxxxxxxxxx>
AuthorDate: Mon, 18 Feb 2013 12:53:37 +0000
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 18 Feb 2013 15:05:57 +0100

printk: Fix rq->lock vs logbuf_lock unlock lock inversion

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

Signed-off-by: ybu <ybu@xxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/E807E903FE6CBE4D95E420FBFCC273B827413C@xxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
kernel/printk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk.c b/kernel/printk.c
index 267ce78..e698e80 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1358,9 +1358,9 @@ static int console_trylock_for_printk(unsigned int cpu)
logbuf_cpu = UINT_MAX;
+ raw_spin_unlock(&logbuf_lock);
if (wake)
- raw_spin_unlock(&logbuf_lock);
return retval;

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