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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 ABF85C433DB for ; Mon, 18 Jan 2021 15:10:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8107722BEA for ; Mon, 18 Jan 2021 15:10:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405413AbhARPJQ (ORCPT ); Mon, 18 Jan 2021 10:09:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:34192 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390787AbhARLmp (ORCPT ); Mon, 18 Jan 2021 06:42:45 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DC2CE22D6F; Mon, 18 Jan 2021 11:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610970139; bh=bpaQKIZvd4zoW/KfB27aVIPVlOHiIh2TQhLtNqawqwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2u4z+izqq2asg2Rywtszeuk+Anb7ryE9JvjgbDadIuV9HIIflVsFMU8Iw0qIA3tZx 1nRvi8FnXTF90vKp2BXGFkCoFrqXgh9HBICHOIIDN7QEdTg+gnJZbkNoyjGdV3i3a/ 0LUm6tSHRkT0Jl1jx5w9PwPf7OAcqWh3xMCKC5P4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Begunkov , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 053/152] io_uring: dont take files/mm for a dead task Date: Mon, 18 Jan 2021 12:33:48 +0100 Message-Id: <20210118113355.336971937@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113352.764293297@linuxfoundation.org> References: <20210118113352.764293297@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pavel Begunkov [ Upstream commit 621fadc22365f3cf307bcd9048e3372e9ee9cdcc ] 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 Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/io_uring.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 4833b68f1a1cc..6c356b9e87b39 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1009,6 +1009,8 @@ 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; -- 2.27.0