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=-16.8 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_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 7EC5BC433FE for ; Wed, 22 Sep 2021 10:13:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62C126120C for ; Wed, 22 Sep 2021 10:13:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234762AbhIVKOc (ORCPT ); Wed, 22 Sep 2021 06:14:32 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:36632 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234795AbhIVKOQ (ORCPT ); Wed, 22 Sep 2021 06:14:16 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R511e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UpDsdJl_1632305558; Received: from e18g09479.et15sqa.tbsite.net(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UpDsdJl_1632305558) by smtp.aliyun-inc.com(127.0.0.1); Wed, 22 Sep 2021 18:12:46 +0800 From: Hao Xu To: Jens Axboe Cc: io-uring@vger.kernel.org, Pavel Begunkov , Joseph Qi Subject: [PATCH 1/3] io_uring: fix race between poll completion and cancel_hash insertion Date: Wed, 22 Sep 2021 18:12:36 +0800 Message-Id: <20210922101238.7177-2-haoxu@linux.alibaba.com> X-Mailer: git-send-email 2.24.4 In-Reply-To: <20210922101238.7177-1-haoxu@linux.alibaba.com> References: <20210922101238.7177-1-haoxu@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org If poll arming and poll completion runs parallelly, there maybe races. For instance, run io_poll_add in iowq and io_poll_task_func in original context, then: iowq original context io_poll_add vfs_poll (interruption happens tw queued to original context) io_poll_task_func generate cqe del from cancel_hash[] if !poll.done insert to cancel_hash[] The entry left in cancel_hash[], similar case for fast poll. Fix it by set poll.done = true when del from cancel_hash[]. Fixes: 5082620fb2ca ("io_uring: terminate multishot poll for CQ ring overflow") Signed-off-by: Hao Xu --- fs/io_uring.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 91e4c89abf78..4b0a40ad28b0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5340,10 +5340,8 @@ static bool __io_poll_complete(struct io_kiocb *req, __poll_t mask) } if (req->poll.events & EPOLLONESHOT) flags = 0; - if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) { - req->poll.done = true; + if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) flags = 0; - } if (flags & IORING_CQE_F_MORE) ctx->cq_extra++; @@ -5374,6 +5372,7 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) if (done) { io_poll_remove_double(req); hash_del(&req->hash_node); + req->poll.done = true; } else { req->result = 0; add_wait_queue(req->poll.head, &req->poll.wait); @@ -5511,6 +5510,7 @@ static void io_async_task_func(struct io_kiocb *req, bool *locked) hash_del(&req->hash_node); io_poll_remove_double(req); + apoll->poll.done = true; spin_unlock(&ctx->completion_lock); if (!READ_ONCE(apoll->poll.canceled)) -- 2.24.4