Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755880Ab2BGGtn (ORCPT ); Tue, 7 Feb 2012 01:49:43 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:61195 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754070Ab2BGGtm (ORCPT ); Tue, 7 Feb 2012 01:49:42 -0500 Date: Tue, 7 Feb 2012 10:49:39 +0400 From: Anton Vorontsov To: Oleg Nesterov Cc: Greg KH , KOSAKI Motohiro , "Eric W. Biederman" , "Paul E. McKenney" , Paul Mundt , Russell King , Mike Frysinger , Benjamin Herrenschmidt , Richard Weinberger , linux-kernel@vger.kernel.org Subject: [PATCH 1/8] sysrq: Fix possible race with exiting task Message-ID: <20120207064939.GA1496@oksana.dev.rtsoft.ru> References: <20120207064809.GA29061@oksana.dev.rtsoft.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120207064809.GA29061@oksana.dev.rtsoft.ru> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1028 Lines: 35 sysrq should grab the tasklist lock, otherwise calling force_sig() is not safe, as it might race with exiting task, which ->sighand might be set to NULL already. Signed-off-by: Anton Vorontsov --- drivers/tty/sysrq.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 7867b7c..a1bcad7 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -322,11 +322,13 @@ static void send_sig_all(int sig) { struct task_struct *p; + read_lock(&tasklist_lock); for_each_process(p) { if (p->mm && !is_global_init(p)) /* Not swapper, init nor kernel thread */ force_sig(sig, p); } + read_unlock(&tasklist_lock); } static void sysrq_handle_term(int key) -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/