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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 F39BEC4332B for ; Mon, 11 Jan 2021 04:04:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C337C227C3 for ; Mon, 11 Jan 2021 04:04:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727041AbhAKEEz (ORCPT ); Sun, 10 Jan 2021 23:04:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725824AbhAKEEz (ORCPT ); Sun, 10 Jan 2021 23:04:55 -0500 Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B90BDC061795; Sun, 10 Jan 2021 20:04:14 -0800 (PST) Received: by mail-wm1-x32d.google.com with SMTP id 3so13717056wmg.4; Sun, 10 Jan 2021 20:04:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=YtyEgNKIS4L+pfBHOPculvaKhcVREy7GPu2xVWuzm2s=; b=SlTOULy9tk/yRruDhD3atnfZ4NTdIjSxK07DuV3EJzl0OL51vx9GhcfuSDSYVXWG/R Xo/DrS/UZdNN+UaWLtnUsg4d311u4hKZJsvpfE1klRD5kmnbHS+24dREoGYaO69dntCi FLePfPC9wGQ7gfp1OeDxVmnWFbNUOprZrH/ip1/xnVHvAGBJecfV4UIxRXtMmvVl0vrq sqoKvgev2dihJktZYmX6B4kO7FVX4cLlKawMqdWjV0jDlsK6tTjb8Q4MyPdtA+JLCvd6 dAFgnnhw0cKZJ6QlZbtG6aslbpvrQftG/nNPtEg7Zh1rH1C1bKrpSFbiLVDbYZOlyKPD yIOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=YtyEgNKIS4L+pfBHOPculvaKhcVREy7GPu2xVWuzm2s=; b=LUm4CzK3J4pjUuB/X3BzKRgPh4LXoz/jLqbYkvHToPD4o/d7cpQZhmUTQZ0tU8XE7q SE/xIP0OjCCB7Gylqe9Xv+ZXFUj7Xsh73NVw9/hQpIA3Fmr5jIcSSMUYdO8gQ/GD0Q/O VgmNilpWXCSsL4x7DqrONfY/j1uArPukIecs3F6z9aYL7e7IjPPcnB4NvyG+giZX5iOr I8sNeyFMhooC277rs9t2G5V49qSkk6H6bSKJV3EgWP/l1lVWKm/tGHGamDoLBGLLNGN5 +2A4XSsKfEDA9G6BWyKNsAQElbwTD2PG7pVn3ymIp6h31ewqf8aDqeJ/pV4TloVgux0g MDIA== X-Gm-Message-State: AOAM530ZAbT1mcZBAUCixcD0X6w/aSb4AuMH52nJ33q7/COfQSJa0pww AMJMe+TjQbo3RpXgzooZOqZVrmErMKA= X-Google-Smtp-Source: ABdhPJyNKp2gKaFsj9crBQZm5oikCOqkgdz8zVZsKpL1xjuUpw0IL62aOrV4J9WpbmfsKCfhn5rTHg== X-Received: by 2002:a1c:2003:: with SMTP id g3mr13011338wmg.136.1610337853507; Sun, 10 Jan 2021 20:04:13 -0800 (PST) Received: from localhost.localdomain ([85.255.237.6]) by smtp.gmail.com with ESMTPSA id o8sm22658061wrm.17.2021.01.10.20.04.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 10 Jan 2021 20:04:13 -0800 (PST) From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org Cc: stable@vger.kernel.org Subject: [PATCH 2/2] io_uring: don't take files/mm for a dead task Date: Mon, 11 Jan 2021 04:00:31 +0000 Message-Id: <0c0af65180413ebfdd0ba376d185906573fe6396.1610337318.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org In rare cases a task may be exiting while io_ring_exit_work() trying to cancel/wait its requests. It's ok for __io_sq_thread_acquire_mm() because of SQPOLL check, but is not for __io_sq_thread_acquire_files(). Play safe and fail for both of them. Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Pavel Begunkov --- fs/io_uring.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 7af74c1ec909..b0e6d8e607a3 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1106,6 +1106,9 @@ static void io_sq_thread_drop_mm_files(void) static int __io_sq_thread_acquire_files(struct io_ring_ctx *ctx) { + if (current->flags & PF_EXITING) + return -EFAULT; + if (!current->files) { struct files_struct *files; struct nsproxy *nsproxy; @@ -1133,6 +1136,8 @@ static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx) { struct mm_struct *mm; + if (current->flags & PF_EXITING) + return -EFAULT; if (current->mm) return 0; -- 2.24.0