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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50879C433FE for ; Mon, 27 Sep 2021 17:25:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F6A861074 for ; Mon, 27 Sep 2021 17:25:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237184AbhI0R0s (ORCPT ); Mon, 27 Sep 2021 13:26:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:37506 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237231AbhI0RYr (ORCPT ); Mon, 27 Sep 2021 13:24:47 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9A3066124B; Mon, 27 Sep 2021 17:15:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632762952; bh=CkVxm4qE455LDkYcWn6RAzTDGpCIyo60uvJ1XDLToko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zFebB4mZPbE8V7X0DxXGxI9Bck0JKZaOqut9dVKbX1bxOeCKtaZj+p1NOF7+EfSfD PH0ozhYuJiC4QCzj+YOhZQ7Q0I0yBRt4/X90yIcxnLOPLsHyNpGxXIEpXrUemUCalO I3jiV2bEqHLa0Pt9TxtboCWyBIrMAc2HYmCBMMHY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hao Xu , Jens Axboe , Sasha Levin Subject: [PATCH 5.14 112/162] io_uring: fix race between poll completion and cancel_hash insertion Date: Mon, 27 Sep 2021 19:02:38 +0200 Message-Id: <20210927170237.331624373@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210927170233.453060397@linuxfoundation.org> References: <20210927170233.453060397@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: stable@vger.kernel.org From: Hao Xu [ Upstream commit bd99c71bd14072ce2920f6d0c2fe43df072c653c ] If poll arming and poll completion runs in parallel, 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 Link: https://lore.kernel.org/r/20210922101238.7177-2-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- 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 754d59f734d8..27a1c813f1e1 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4968,10 +4968,8 @@ 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++; @@ -4993,6 +4991,7 @@ static void io_poll_task_func(struct io_kiocb *req) 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); @@ -5126,6 +5125,7 @@ static void io_async_task_func(struct io_kiocb *req) hash_del(&req->hash_node); io_poll_remove_double(req); + apoll->poll.done = true; spin_unlock_irq(&ctx->completion_lock); if (!READ_ONCE(apoll->poll.canceled)) -- 2.33.0