From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, ybu , Peter Zijlstra , Thomas Gleixner , Ben Hutchings , Qiang Huang , Li Zefan , Jianguo Wu Subject: [PATCH 3.4 004/134] printk: Fix rq->lock vs logbuf_lock unlock lock inversion Date: Wed, 9 Apr 2014 20:22:00 -0700 Message-Id: <20140410032300.218633795@linuxfoundation.org> In-Reply-To: <20140410032259.587501440@linuxfoundation.org> References: <20140410032259.587501440@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Bu, Yitian" 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 Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/E807E903FE6CBE4D95E420FBFCC273B827413C@nasanexd01h.na.qualcomm.com Signed-off-by: Thomas Gleixner [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings Cc: Qiang Huang Cc: Li Zefan Cc: Jianguo Wu Signed-off-by: Greg Kroah-Hartman --- kernel/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/printk.c +++ b/kernel/printk.c @@ -822,9 +822,9 @@ static int console_trylock_for_printk(un } } 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 [] =