From patchwork Mon Jan 18 11:33:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 366030 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=ham 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 3284BC4332B for ; Mon, 18 Jan 2021 15:03:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0642622BF3 for ; Mon, 18 Jan 2021 15:03:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405282AbhARPDK (ORCPT ); Mon, 18 Jan 2021 10:03:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:37702 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390799AbhARLmy (ORCPT ); Mon, 18 Jan 2021 06:42:54 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 135FF22D70; Mon, 18 Jan 2021 11:42:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610970141; bh=MhgRcf7sqHECTaVMRMeimJpL+lflvD4YZfgi2ggkGZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j5pVld6lFoowFFJ/lzSPFNnd2kSjtYIa4kwx7YcSXvqZi/JqoZYyrLwawnVRGU/DD cBKeXDF575Hd3Qbbdq7wn2emuB1nSeklUbGJp5lHGXXuiJwIxp2ONQPOvrTAZFrf8Q bcHkuXAmKPaB2ffkyHsoAnCrjNNeIIL90Cv7K1OI= 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 5.10 054/152] io_uring: drop mm and files after task_work_run Date: Mon, 18 Jan 2021 12:33:49 +0100 Message-Id: <20210118113355.385620010@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 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pavel Begunkov [ Upstream commit d434ab6db524ab1efd0afad4ffa1ee65ca6ac097 ] __io_req_task_submit() run by task_work can set mm and files, but io_sq_thread() in some cases, and because __io_sq_thread_acquire_mm() and __io_sq_thread_acquire_files() do a simple current->mm/files check it may end up submitting IO with mm/files of another task. We also need to drop it after in the end to drop potentially grabbed references to them. Cc: stable@vger.kernel.org # 5.9+ 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 6c356b9e87b39..cab640c10bc0f 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6841,6 +6841,7 @@ static int io_sq_thread(void *data) if (ret & SQT_SPIN) { io_run_task_work(); + io_sq_thread_drop_mm(); cond_resched(); } else if (ret == SQT_IDLE) { if (kthread_should_park()) @@ -6855,6 +6856,7 @@ static int io_sq_thread(void *data) } io_run_task_work(); + io_sq_thread_drop_mm(); if (cur_css) io_sq_thread_unassociate_blkcg();