| Subject: printk: Fix rq->lock vs logbuf_lock unlock lock inversion |
| From: "Bu, Yitian" <ybu@qti.qualcomm.com> |
| Date: Mon, 18 Feb 2013 12:53:37 +0000 |
| |
| 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> |
| Cc: stable@vger.kernel.org |
| Cc: stable-rt@vger.kernel.org |
| Link: http://lkml.kernel.org/r/E807E903FE6CBE4D95E420FBFCC273B827413C@nasanexd01h.na.qualcomm.com |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| kernel/printk.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| Index: linux-stable/kernel/printk.c |
| =================================================================== |
| --- linux-stable.orig/kernel/printk.c |
| +++ linux-stable/kernel/printk.c |
| @@ -1412,9 +1412,9 @@ static int console_trylock_for_printk(un |
| } |
| } |
| logbuf_cpu = UINT_MAX; |
| + raw_spin_unlock(&logbuf_lock); |
| if (wake) |
| up(&console_sem); |
| - raw_spin_unlock(&logbuf_lock); |
| return retval; |
| } |
| |
