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 X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=FORGED_MUA_MOZILLA, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1479C4332B for ; Fri, 20 Mar 2020 20:27:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FD5020786 for ; Fri, 20 Mar 2020 20:27:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727135AbgCTU1s (ORCPT ); Fri, 20 Mar 2020 16:27:48 -0400 Received: from mail-oln040092074062.outbound.protection.outlook.com ([40.92.74.62]:50153 "EHLO EUR04-DB3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726789AbgCTU1s (ORCPT ); Fri, 20 Mar 2020 16:27:48 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=VAtsIeEBjXbaQ3mdg4TlfmCbgXXEFw7FElal2WRXFftl38kccc9fJEvkvWA5Rsa7OiHdwr6t26axOdBovZrjiu3FdUXN7o06EWoblxrQyxysht80U5pooIHXD3zq96J52sCtose2AEh0SYN7RoYcW+ld8nQdVsqApD1j3wYeRF6XoAvo2/APFIwxZdH0WcI/5HMH0goUEhHm+UtKGs+HxKa5/4zYM2uUfA4khzGpEsS2owLOyniR6FVBuLyq8g5kf/yJBgsXVdigB0F8vtpfAG0Ns6XFMWqXDIOzbBZlraNbs3yFrRWEgCP57oQNV2CnabX6NmbE0xAUxMWNSUJ8KQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=JNoysm1NEM+uK0Qpok8HGY+SdB/cu3DfrcgQyZJAOyQ=; b=GJeslHd6oZBtoWhgH6cVYLiBaLvLgWWoh9BsU2p5BLxkVGHKQRDc5Dm1i5zTokz2aku0k6HPaSy4Xup1KEecLp0alL/PUiSPrDkUHsO3nYTN3nw3JfjuGuXNeEt+7KmHE8oSfE2m5HV5btj+o6qNqUNLsnBMRn7T1ruDwMV23BuUMjo5DtyJDVnBCpXWcHcBiAz57N40rZZRK2aNrRt/IXesRHYNhJVVm3My5I62ZpMoWcz8LM2dRM1PnpG57Wm/RuL2ga+tqFS27LiEISO5PJal8VvECYF5NzAe5KH6rvoaTGnLFtJEHeGE8s7JHiCVU2wBfqeSODsnBWVMvhp/4w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=hotmail.de; dmarc=pass action=none header.from=hotmail.de; dkim=pass header.d=hotmail.de; arc=none Received: from DB3EUR04FT027.eop-eur04.prod.protection.outlook.com (2a01:111:e400:7e0c::35) by DB3EUR04HT134.eop-eur04.prod.protection.outlook.com (2a01:111:e400:7e0c::356) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2814.13; Fri, 20 Mar 2020 20:27:45 +0000 Received: from AM6PR03MB5170.eurprd03.prod.outlook.com (10.152.24.52) by DB3EUR04FT027.mail.protection.outlook.com (10.152.24.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2814.13 via Frontend Transport; Fri, 20 Mar 2020 20:27:44 +0000 X-IncomingTopHeaderMarker: OriginalChecksum:65D9A53059D0CA393912EACF28F4CF314EF9AF6B3DD0105B6F1F371DE17F8FA0;UpperCasedChecksum:3D462F6C3FF845464835E354DF74519615C4760264D46DF00FD5682C06B58D94;SizeAsReceived:9420;Count:49 Received: from AM6PR03MB5170.eurprd03.prod.outlook.com ([fe80::1956:d274:cab3:b4dd]) by AM6PR03MB5170.eurprd03.prod.outlook.com ([fe80::1956:d274:cab3:b4dd%6]) with mapi id 15.20.2835.017; Fri, 20 Mar 2020 20:27:44 +0000 From: Bernd Edlinger Subject: [PATCH v6 12/16] proc: io_accounting: Use new infrastructure to fix deadlocks in execve To: Greg Kroah-Hartman , Kirill Tkhai , "Eric W. Biederman" , Christian Brauner , Kees Cook , Jann Horn , Jonathan Corbet , Alexander Viro , Andrew Morton , Alexey Dobriyan , Thomas Gleixner , Oleg Nesterov , Frederic Weisbecker , Andrei Vagin , Ingo Molnar , "Peter Zijlstra (Intel)" , Yuyang Du , David Hildenbrand , Sebastian Andrzej Siewior , Anshuman Khandual , David Howells , James Morris , Shakeel Butt , Jason Gunthorpe , Christian Kellner , Andrea Arcangeli , Aleksa Sarai , "Dmitry V. Levin" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "stable@vger.kernel.org" , "linux-api@vger.kernel.org" References: <077b63b7-6f5e-aa8e-bf96-a586b481cc46@hotmail.de> Message-ID: Date: Fri, 20 Mar 2020 21:27:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 In-Reply-To: <077b63b7-6f5e-aa8e-bf96-a586b481cc46@hotmail.de> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: ZR0P278CA0021.CHEP278.PROD.OUTLOOK.COM (2603:10a6:910:1c::8) To AM6PR03MB5170.eurprd03.prod.outlook.com (2603:10a6:20b:ca::23) X-Microsoft-Original-Message-ID: <8decd8ec-90e8-373e-7936-d8b6b1e5341d@hotmail.de> MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.1.101] (92.77.140.102) by ZR0P278CA0021.CHEP278.PROD.OUTLOOK.COM (2603:10a6:910:1c::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2835.19 via Frontend Transport; Fri, 20 Mar 2020 20:27:43 +0000 X-Microsoft-Original-Message-ID: <8decd8ec-90e8-373e-7936-d8b6b1e5341d@hotmail.de> X-TMN: [N+35OmbNjv1CQNurlagqYXNCeAVMja6i] X-MS-PublicTrafficType: Email X-IncomingHeaderCount: 49 X-EOPAttributedMessage: 0 X-MS-Office365-Filtering-Correlation-Id: ad62df84-7b0d-4c27-ece6-08d7cd0d25a6 X-MS-TrafficTypeDiagnostic: DB3EUR04HT134: X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: CMmIEn7POoXmYwst3A8Ac+Npt/0Xx0XLq7/Uu/GArKPvAa7GWRJFKTRFlZMUo8DDPrGvcV9vVV0FiOvgzjwJrymGYzKoJMUH3Qb7gmvmqoKwB139tKa1k7YzSVh3ip5ZMwKwEl7Sf6BsOSvP6srPxtJyHNSdC4ULFMw8OmxvYHiPhwN3q3hPmKZ7LLFcZnWi X-MS-Exchange-AntiSpam-MessageData: KIhviCliUNuh0YvP/mxJmNKch9/Kc9L0JYtbAZKTGds6AVrrdp3D+i8By6fjcEAKZnfY1cMesz6DkrBgTyE88+srVqJsByJjAJ4fklIS7suTwW4c05s1CWP0p5zwGx9MdseVUTIjuA5xBoEpl457QQ== X-OriginatorOrg: outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: ad62df84-7b0d-4c27-ece6-08d7cd0d25a6 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Mar 2020 20:27:44.9128 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-CrossTenant-FromEntityHeader: Internet X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB3EUR04HT134 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This changes do_io_accounting to use the new exec_update_mutex instead of cred_guard_mutex. This fixes possible deadlocks when the trace is accessing /proc/$pid/io for instance. This should be safe, as the credentials are only used for reading. Signed-off-by: Bernd Edlinger --- fs/proc/base.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index fed76abf..6b13fc4 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2861,7 +2861,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh unsigned long flags; int result; - result = mutex_lock_killable(&task->signal->cred_guard_mutex); + result = mutex_lock_killable(&task->signal->exec_update_mutex); if (result) return result; @@ -2897,7 +2897,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh result = 0; out_unlock: - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); return result; } -- 1.9.1