From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752684AbbKPSUU (ORCPT ); Mon, 16 Nov 2015 13:20:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44967 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751342AbbKPSUT (ORCPT ); Mon, 16 Nov 2015 13:20:19 -0500 From: Vitaly Kuznetsov To: Andrew Morton Cc: linux-kernel@vger.kernel.org, HATAYAMA Daisuke , Masami Hiramatsu , Jiri Kosina , Baoquan He , Prarit Bhargava , Xie XiuQi , Seth Jennings , "K. Y. Srinivasan" , Jan Kara , Petr Mladek , Yasuaki Ishimatsu Subject: [PATCH] panic: turn off locks debug before releasing console lock Date: Mon, 16 Nov 2015 19:20:14 +0100 Message-Id: <1447698014-17844-1-git-send-email-vkuznets@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 08d78658f393 ("panic: release stale console lock to always get the logbuf printed out") introduced unwanted bad unlock balance report when panic() is called directly and not from OOPS (e.g. from out_of_memory()). The difference is that in case of OOPS we disable locks debug in oops_enter() and on direct panic call nobody does that. Fixes: 08d78658f393 ("panic: release stale console lock to always get the logbuf printed out") Reported-by: kernel test robot Signed-off-by: Vitaly Kuznetsov Cc: HATAYAMA Daisuke Cc: Masami Hiramatsu Cc: Jiri Kosina Cc: Baoquan He Cc: Prarit Bhargava Cc: Xie XiuQi Cc: Seth Jennings Cc: "K. Y. Srinivasan" Cc: Jan Kara Cc: Petr Mladek Cc: Yasuaki Ishimatsu --- The original plan was to replace this patch with less hackish implementation from Jan's "printk: Softlockup avoidance" series but it seems it didn't get merged in 4.4 so we still need some band-aid for now. --- kernel/panic.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/panic.c b/kernel/panic.c index 4579dbb..4b150bc 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -152,8 +152,11 @@ void panic(const char *fmt, ...) * We may have ended up stopping the CPU holding the lock (in * smp_send_stop()) while still having some valuable data in the console * buffer. Try to acquire the lock then release it regardless of the - * result. The release will also print the buffers out. + * result. The release will also print the buffers out. Locks debug + * should be disabled to avoid reporting bad unlock balance when + * panic() is not being callled from OOPS. */ + debug_locks_off(); console_trylock(); console_unlock(); -- 2.4.3