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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 813A1C388F9 for ; Tue, 3 Nov 2020 20:40:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 144082236F for ; Tue, 3 Nov 2020 20:40:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436028; bh=IWxqs2X63agThMfuF3hPsQ3OgyfHQ83oTP7Q4kzW7JA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Dh3f+LYyN/c0omHV4aScvyZ9wGnhcbvrTZ1WgQmLhjT4oEdYZGnPHzuKWuPfsxbGK Lr4fci/8yAzbROxNU4FznKmtQsg5zrp8jJMxVwhKTjKaC86K5UlF3r7NEgekv3CJ59 6gZAY0vrGCc2nhei/++KXp83pYoR3YyDiVDpIQ3M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730212AbgKCUkZ (ORCPT ); Tue, 3 Nov 2020 15:40:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:51638 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729787AbgKCUkW (ORCPT ); Tue, 3 Nov 2020 15:40:22 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F17F0223AC; Tue, 3 Nov 2020 20:40:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436022; bh=IWxqs2X63agThMfuF3hPsQ3OgyfHQ83oTP7Q4kzW7JA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aogMO7yyvOigFeMl6w34ut0hVMj0qXyK83Bf8so8kXtcznxXOT5EVrelGDb1UeDkg IWjzbtVChFdHCSni1/IEzi6pjNxl9ow56+mEskpUni2AphaQzBGJAnKJicImD7RK90 lfKRzJjDQDdNPKujoVYkt5BpEtrKmwqv/ZwBhI/8= 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 5.9 070/391] io_uring: dont set COMP_LOCKED if wont put Date: Tue, 3 Nov 2020 21:32:01 +0100 Message-Id: <20201103203351.972293956@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203348.153465465@linuxfoundation.org> References: <20201103203348.153465465@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 368c5481ae7c6a9719c40984faea35480d9f4872 ] __io_kill_linked_timeout() sets REQ_F_COMP_LOCKED for a linked timeout even if it can't cancel it, e.g. it's already running. It not only races with io_link_timeout_fn() for ->flags field, but also leaves the flag set and so io_link_timeout_fn() may find it and decide that it holds the lock. Hopefully, the second problem is potential. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/io_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 59ab8c5c2aaaa..50a7a99dad4ca 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1650,6 +1650,7 @@ static bool io_link_cancel_timeout(struct io_kiocb *req) ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret != -1) { + req->flags |= REQ_F_COMP_LOCKED; io_cqring_fill_event(req, -ECANCELED); io_commit_cqring(ctx); req->flags &= ~REQ_F_LINK_HEAD; @@ -1672,7 +1673,6 @@ static bool __io_kill_linked_timeout(struct io_kiocb *req) return false; list_del_init(&link->link_list); - link->flags |= REQ_F_COMP_LOCKED; wake_ev = io_link_cancel_timeout(link); req->flags &= ~REQ_F_LINK_TIMEOUT; return wake_ev; -- 2.27.0