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 CA1B9C54E94 for ; Thu, 26 Jan 2023 04:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230273AbjAZEnh (ORCPT ); Wed, 25 Jan 2023 23:43:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229446AbjAZEnc (ORCPT ); Wed, 25 Jan 2023 23:43:32 -0500 Received: from NAM10-DM6-obe.outbound.protection.outlook.com (mail-dm6nam10on2083.outbound.protection.outlook.com [40.107.93.83]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AB8D7DB8; Wed, 25 Jan 2023 20:43:31 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=lxjHi8xCdsQ6sLf3zuDSRuFUe2uBX3rcgf0w95MJnKIF0UyTPa5Byrz8HNy8zYtdQWZFWQ3h2dR+ODWn0+c5d8Fxz+xk7L37fTKn4h28dWenV24NYFfPC4iPKKPazQvWTDHRQpV+6VywPuoEg9Q0SSRCThSm3EU5EGd69W6APc56UZRvVFf3k2i/PlW3y1rI8UboGeIZK9VPpM3OCkDfbkhSaCFyGKHP7GybkgTrOXOnrSENm+XuhuEb3TxbU0jqvHizivHIJUxrnlHcNXz21AItwl0dnV0H0jpHz/bQsf0VTYoYMdCbD9tEyWf3UdbwHnpBgeq0Bo9tS7QmM2wbMg== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=LenMtkMaUOie3PCzbVdzSBBbokNi88XcC8DwVG6zJyM=; b=Qgm4fZoDEye/lcaYFRizoTRJ3RYDE2dReVU9jDNiUrA+JV2cQUXGpdrLHkBBtczatQSpf3jj23U6veX8ohcsS0ZF/h7IWoNMpezIZwUV49jBBNl6iU8p4EtciGOy/PUuWJnP2uaejwwnVPgMXOGp6YgCKgWrbIUBz56HEIYfeQ9UcXbu+MtAO575VbY9fZUkQMIdV651xfF5q5dN3RXdtoDYPU7e8FvBpBl3z/zQtHDAYYIhCPSQgJxSByBtqektpncvp2cT5HpoL4NF4D51jyVb7lDPS8DecEgAatbyPkm1t4YDrDwnYHhRDomKecrh43YFodj3whZxE0cCU/iRjw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=memverge.com; dmarc=pass action=none header.from=memverge.com; dkim=pass header.d=memverge.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=memverge.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=LenMtkMaUOie3PCzbVdzSBBbokNi88XcC8DwVG6zJyM=; b=WSzeHhKV63skckg/dfSUfxhU1FF3hvpmTW/nODN2wOzoZUnSnx0boP1KCwCkbbrD2lVMtTzBJ755bLB7jQobpbNu3rAC4Bh1JnhLj19tS9ANik5ZV1x/FtvdVIhDlo1B2t0LAY3zwDPz772zhPsyNWBvLNDpKhr/CNiY8Q4Zlm8= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=memverge.com; Received: from BN6PR17MB3121.namprd17.prod.outlook.com (2603:10b6:405:7c::19) by SJ0PR17MB5857.namprd17.prod.outlook.com (2603:10b6:a03:40c::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6002.33; Thu, 26 Jan 2023 04:43:28 +0000 Received: from BN6PR17MB3121.namprd17.prod.outlook.com ([fe80::d253:1eb3:9347:c660]) by BN6PR17MB3121.namprd17.prod.outlook.com ([fe80::d253:1eb3:9347:c660%4]) with mapi id 15.20.6002.033; Thu, 26 Jan 2023 04:43:28 +0000 Date: Wed, 25 Jan 2023 23:43:18 -0500 From: Gregory Price To: Oleg Nesterov Cc: Gregory Price , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, avagin@gmail.com, peterz@infradead.org, luto@kernel.org, krisman@collabora.com, tglx@linutronix.de, corbet@lwn.net, shuah@kernel.org Subject: Re: [PATCH v6 1/2] ptrace,syscall_user_dispatch: Implement Syscall User Dispatch Suspension Message-ID: References: <20230125025126.787431-1-gregory.price@memverge.com> <20230125025126.787431-2-gregory.price@memverge.com> <20230126003008.GA31684@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230126003008.GA31684@redhat.com> X-ClientProxiedBy: BYAPR02CA0006.namprd02.prod.outlook.com (2603:10b6:a02:ee::19) To BN6PR17MB3121.namprd17.prod.outlook.com (2603:10b6:405:7c::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN6PR17MB3121:EE_|SJ0PR17MB5857:EE_ X-MS-Office365-Filtering-Correlation-Id: c3d04389-0a7c-48c7-79c6-08daff57de1d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BN6PR17MB3121.namprd17.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230025)(346002)(366004)(39840400004)(376002)(136003)(396003)(451199018)(2616005)(36756003)(2906002)(86362001)(4326008)(83380400001)(44832011)(8936002)(66476007)(316002)(478600001)(38100700002)(7416002)(6486002)(5660300002)(6506007)(186003)(6916009)(8676002)(26005)(6512007)(66946007)(66556008)(41300700001)(6666004);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?UDXE8rul8qXVhfn0umWIZ1yHHOFVJVPxbidN1ZLpJfm0fXhl1uEQ8P6wnuW0?= =?us-ascii?Q?dmWdTe2QD0H5L1LAsmJW8goDvzU0NYSTubGo/hs3xsBg9stplifzS0iPyxG/?= =?us-ascii?Q?D7SUmQjxC5sYoz0uxt6x1dSrqbmYyxK3JvS/y2U/DOGvJ3G8eNGi8paaWlHj?= =?us-ascii?Q?T6qHjCBO+BgXplgIopnFVIKBzazw0Zg6Lob5FaLziuZrvE5vjYRzFHR7dDSf?= =?us-ascii?Q?rZYHumhj/xQAY2knSy/jaq27KDpxUGQaAu+eOyMsC+WvvdgoUQKYEliPV2as?= =?us-ascii?Q?7hAGjk621bi0HWn849w6GuGCAahvdw4zmEyfrPlswdHmex0eMTlZ79ULhev2?= =?us-ascii?Q?r+kG56GuAo5v3iz91xicty6LOXsDvxRUXF1+1NGbt28LiJ3fEOb6Yq3GX3YJ?= =?us-ascii?Q?q1T+A7vkazYE1j/3cvmlD0gUzgvwX+U1pmGGJO7Rr3S2rk0/beSuQs14IJa9?= =?us-ascii?Q?rN1NDHnk46c1IqcWhh9SNDZcvn+sF+G0swUDdKMKQ2u9Cpi7s2Z/uJULX4vU?= =?us-ascii?Q?ZLLwfg6poqDrC+GAIisxwhEHb90rYIRuT71H4B9EPiGAVkAJna/GKPGKacQj?= =?us-ascii?Q?FGeV1hgZT6/0lehjD7KFO3q7HALAsDp9WKijPZ+XeZ4Qvea/QqfChJiy6RoM?= =?us-ascii?Q?Qzd6u/DYxEw6mDG9vLsdzcfoyyI0HvHX5X9Jb3hNd/Dpnag+MDzK86FwHxah?= =?us-ascii?Q?o+iwvg94Miq5UDYyJXgJl5UH/Ixvg73lZL9l3CXulRBbkO3UozOR1ObP8jod?= =?us-ascii?Q?4jEtzORjM/x55Erecc1/8mYxMfrOqG9BlMuNX1IE9MlxwTBTG9tri4QuRnkK?= =?us-ascii?Q?CXSMaBWDJVYxMAVM2MvTlg+GVvnAgtVbe6swft7OXQ6qwNyjPfAMUxQmjTsk?= =?us-ascii?Q?B21gwTXiS4v5tAiKH8jclaKJ5PzmquAtUvBx2Xy+IM6tlVjf4bklSoREWJoV?= =?us-ascii?Q?RGfb2qWwxhWU89W5+SvR+3GiIUE/Byx4AjzVqhoOMp0qfEei7zocJ5nJWxPA?= =?us-ascii?Q?QM9a6jDoAfjBrjNv14yF9R7cJoRQvZTuXSvA/F4old/8f33x+GH8k2jXIDu/?= =?us-ascii?Q?b82VRqQHTt2ZAOCyUgmmEBOWd/orJZgMg9rJ0T6TYJL3O8jjb4L1cs8h/Ply?= =?us-ascii?Q?RnxIl1LwywSL26foX+gksCtoS7YUkYOxMZ7Z8oMG+nxfeMWdSLAOJEAmloSB?= =?us-ascii?Q?s8ylvwUJ7sqoZRtDlwdJ6oWlfs7ZnDmxQZgCQOmqiDIaUQmEVbr8vPr4RUle?= =?us-ascii?Q?jcu6Xpxo+DCqWwitsVu+aw5+gqwBQQfxuc8T2LqAjbI5DeHt4spYbscJZ7cA?= =?us-ascii?Q?PFZG7BmgDHzncETDdnRmPC91BrkmZzRcxyI8DHHkeoxOsScYOKG3ixRoEjS5?= =?us-ascii?Q?ab0/02qEx4pl+sojEkfU4GtZrwb/bur62Z6WCKDbcVohnVxBgx/SdwH3BfKw?= =?us-ascii?Q?km5vF5hT9wEjNojjQxLqgbHKFzNnX2u6dbc9K722uY4jgUNpkrIARK+K0Fji?= =?us-ascii?Q?jg52Xs2LitgiBvyX6sUrenyQ4pIb8zWrejT8dnXnC0waZClZd2WvMqKqroI5?= =?us-ascii?Q?wuZVq+rYxzk/K2UMlDVDmUPiyZYbIF4WWQqYFDokYzWBmhBleSGAco9Q2UR8?= =?us-ascii?Q?fA=3D=3D?= X-OriginatorOrg: memverge.com X-MS-Exchange-CrossTenant-Network-Message-Id: c3d04389-0a7c-48c7-79c6-08daff57de1d X-MS-Exchange-CrossTenant-AuthSource: BN6PR17MB3121.namprd17.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2023 04:43:28.2245 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 5c90cb59-37e7-4c81-9c07-00473d5fb682 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: s+iXwA9uAuqZrPvFZzkYLZNx6DS9kyL4u+f/jXunFZMsoLos857rV3G237I511YVB6M/Nv1gQaY23QVBNdiUH3z4VREfE7mD59HqhiuEGqo= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR17MB5857 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 26, 2023 at 01:30:08AM +0100, Oleg Nesterov wrote: > On 01/24, Gregory Price wrote: > > > > Adds PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH to ptrace options, and > > modify Syscall User Dispatch to suspend interception when enabled. > > > > This is modeled after the SUSPEND_SECCOMP feature, which suspends > > SECCOMP interposition. Without doing this, software like CRIU will > > inject system calls into a process and be intercepted by Syscall > > User Dispatch, either causing a crash (due to blocked signals) or > > the delivery of those signals to a ptracer (not the intended behavior). > > Cough... Gregory, I am sorry ;) > > but can't we drop this patch to ? > > CRIU needs to do PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG and check > config->mode anyway as we discussed. > > Then it can simply set *config->selector = SYSCALL_DISPATCH_FILTER_ALLOW > with the same effect, no? > > Oleg. > After further investigation, I believe we can drop 1/2, but for a different reason: It's actually insane behavior during the quiesce phase. Quiesce allows the program to run until a particular state, which means we can't turn it off lest we interfere with intended behavior - (cough cough prior review said this cough cough i'm dumb). I'll drop patch 1/2 and resubmit (there's an unused variable warning i need to clean up). Thanks again for the reviews all ~Gregory