From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97CA7C433F5 for ; Mon, 10 Oct 2022 08:32:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231280AbiJJIcj (ORCPT ); Mon, 10 Oct 2022 04:32:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231162AbiJJIci (ORCPT ); Mon, 10 Oct 2022 04:32:38 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8089161715 for ; Mon, 10 Oct 2022 01:32:35 -0700 (PDT) Received: from dggpeml500023.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MmBr96qsFzVhxF; Mon, 10 Oct 2022 16:28:09 +0800 (CST) Received: from dggpeml500016.china.huawei.com (7.185.36.70) by dggpeml500023.china.huawei.com (7.185.36.114) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 10 Oct 2022 16:32:33 +0800 Received: from [10.174.176.102] (10.174.176.102) by dggpeml500016.china.huawei.com (7.185.36.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 10 Oct 2022 16:32:33 +0800 Message-ID: <64352d65-dc3e-69ee-cd96-0440a32709d3@huawei.com> Date: Mon, 10 Oct 2022 16:32:32 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH] misc/fsck.c: Processes may kill other processes. To: Lukas Czerner CC: Theodore Ts'o , , , linfeilong References: <01783b8c-2a39-73ec-c537-cc1df82643e2@huawei.com> <20221010071725.ghflyqxj7poqlwtq@fedora> From: zhanchengbin In-Reply-To: <20221010071725.ghflyqxj7poqlwtq@fedora> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.102] X-ClientProxiedBy: dggpeml100017.china.huawei.com (7.185.36.161) To dggpeml500016.china.huawei.com (7.185.36.70) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 2022/10/10 15:17, Lukas Czerner wrote: > On Sat, Oct 08, 2022 at 11:05:48AM +0800, zhanchengbin wrote: >> If run the fsck -N command, processes don't execute, just show what >> would be done. However, the pid whose value is -1 is added to the >> instance_list list in the execute function,if the kill_all function >> is called later, kill(-1, signum) is executed, Signals are sent to >> all processes except the number one process and itself. Other >> processes will be killed if they use the default signal processing >> function. >> >> Signed-off-by: zhanchengbin >> --- >> misc/fsck.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/misc/fsck.c b/misc/fsck.c >> index 4efe10ec..faf7789d 100644 >> --- a/misc/fsck.c >> +++ b/misc/fsck.c >> @@ -546,6 +546,8 @@ static int kill_all(int signum) >> for (inst = instance_list; inst; inst = inst->next) { >> if (inst->flags & FLAG_DONE) >> continue; >> + if (inst->pid == -1) >> + continue; > > That works, but I think we can afford to be a little defensive here. > Anything <= 0 is a bug and can have unexpected consequences if we > actually call the kill(). > > if (inst->pid <= 0) > continue OK, I'll fix this and send the v2 version of the patch. > > > Also as Darrick pointed out we need to send the patch to util-linux > (disk-utils/fsck.c) as well if you haven't already. I'll check and modify util-linux(disk-utils/fsck.c). -zhanchengbin > > -Lukas > > >> kill(inst->pid, signum); >> n++; >> } >> -- >> 2.27.0 >> > > . >