From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751340AbdFENJH (ORCPT ); Mon, 5 Jun 2017 09:09:07 -0400 Received: from mx2.suse.de ([195.135.220.15]:48240 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751280AbdFENJG (ORCPT ); Mon, 5 Jun 2017 09:09:06 -0400 Date: Mon, 5 Jun 2017 15:09:03 +0200 From: Michal Hocko To: zhongjiang Cc: akpm@linux-foundation.org, oleg@redhat.com, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, qiuxishi@huawei.com Subject: Re: [PATCH v2] signal: Avoid undefined behaviour in kill_something_info Message-ID: <20170605130903.GP9248@dhcp22.suse.cz> References: <1496667207-56723-1-git-send-email-zhongjiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1496667207-56723-1-git-send-email-zhongjiang@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 05-06-17 20:53:27, zhongjiang wrote: > diff --git a/kernel/signal.c b/kernel/signal.c > index ca92bcf..63148f7 100644 > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -1395,6 +1395,12 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid) > > read_lock(&tasklist_lock); > if (pid != -1) { > + /* > + * -INT_MIN is undefined, it need to exclude following case to > + * avoid the UBSAN detection. > + */ > + if (pid == INT_MIN) > + return -ESRCH; this will obviously keep the tasklist_lock held... > ret = __kill_pgrp_info(sig, info, > pid ? find_vpid(-pid) : task_pgrp(current)); > } else { > -- > 1.7.12.4 -- Michal Hocko SUSE Labs