From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 3/7] printk: Fix rq->lock vs logbuf_lock unlock lock inversion Date: Mon, 18 Feb 2013 22:53:42 -0500 Message-ID: <20130219035410.384095545@goodmis.org> References: <20130219035339.428477998@goodmis.org> Cc: Thomas Gleixner , Carsten Emde , John Kacur , ybu , Peter Zijlstra , , To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Content-Disposition: inline; filename=0003-printk-Fix-rq-lock-vs-logbuf_lock-unlock-lock-invers.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org From: "Bu, Yitian" 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 Cc: Peter Zijlstra 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 Signed-off-by: Steven Rostedt --- kernel/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/printk.c b/kernel/printk.c index 7109711..56d7497 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -868,9 +868,9 @@ static int console_trylock_for_printk(unsigned int cpu, unsigned long flags) } } printk_cpu = UINT_MAX; + raw_spin_unlock(&logbuf_lock); if (wake) up(&console_sem); - raw_spin_unlock(&logbuf_lock); return retval; } static const char recursion_bug_msg [] = -- 1.7.10.4