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Subject[PATCH] Fix rq->lock vs logbuf_lock unlock race
Date
This patch is for kernel V3.7.9

From 8796f4a2175a323aaa49ea8dd0fe68678dd5dccd Mon Sep 17 00:00:00 2001
From: ybu <ybu@qti.qualcomm.com>
Date: Mon, 18 Feb 2013 19:52:01 +0800
Subject: [PATCH] Fix rq->lock vs logbuf_lock unlock race

fix up the fallout from commit 07354eb1a74d1 ("locking printk:
Annotate logbuf_lock as raw")
Release console_sem after unlocking the logbuf_lock avoids some lock
inversion troubles between logbuf_lock and rq->lock.

Change-Id: I782c1d16e0e82bd156699f0f205f19781c4819e0
Signed-off-by: ybu <ybu@qti.qualcomm.com>
---
kernel/printk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk.c b/kernel/printk.c
index f8e0b5a..3a49454 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1356,9 +1356,9 @@ 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;
}

--
1.7.9.5


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