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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 2C43FC4320A for ; Wed, 1 Sep 2021 09:39:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1696761026 for ; Wed, 1 Sep 2021 09:39:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243703AbhIAJkT (ORCPT ); Wed, 1 Sep 2021 05:40:19 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:42250 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232817AbhIAJkR (ORCPT ); Wed, 1 Sep 2021 05:40:17 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0Umv2h7c_1630489159; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0Umv2h7c_1630489159) by smtp.aliyun-inc.com(127.0.0.1); Wed, 01 Sep 2021 17:39:19 +0800 To: Jens Axboe , Pavel Begunkov , "open list:IO_URING" , open list From: =?UTF-8?B?546L6LSH?= Subject: [RFC PATCH] io_uring: stop issue failed request to fix panic Message-ID: Date: Wed, 1 Sep 2021 17:39:18 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We observed panic: BUG: kernel NULL pointer dereference, address:0000000000000028 [skip] Oops: 0000 [#1] SMP PTI CPU: 1 PID: 737 Comm: a.out Not tainted 5.14.0+ #58 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:vfs_fadvise+0x1e/0x80 [skip] Call Trace: ? tctx_task_work+0x111/0x2a0 io_issue_sqe+0x524/0x1b90 This is caused by io_wq_submit_work() calling io_issue_sqe() on a failed fadvise request, and the io_init_req() return error before initialize the file for it, lead into the panic when vfs_fadvise() try to access 'req->file'. This patch add the missing check & handle for failed request before calling io_issue_sqe(). Signed-off-by: Michael Wang --- fs/io_uring.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6f35b12..bfec7bf 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2214,7 +2214,8 @@ static void io_req_task_submit(struct io_kiocb *req, bool *locked) io_tw_lock(ctx, locked); /* req->task == current here, checking PF_EXITING is safe */ - if (likely(!(req->task->flags & PF_EXITING))) + if (likely(!(req->task->flags & PF_EXITING) && + !(req->flags & REQ_F_FAIL))) __io_queue_sqe(req); else io_req_complete_failed(req, -EFAULT); @@ -6704,7 +6705,10 @@ static void io_wq_submit_work(struct io_wq_work *work) if (!ret) { do { - ret = io_issue_sqe(req, 0); + if (likely(!(req->flags & REQ_F_FAIL))) + ret = io_issue_sqe(req, 0); + else + io_req_complete_failed(req, -EFAULT); /* * We can get EAGAIN for polled IO even though we're * forcing a sync submission from here, since we can't -- 1.8.3.1