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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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=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 60DC1C19F3F for ; Mon, 2 Aug 2021 14:05:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A4576023B for ; Mon, 2 Aug 2021 14:05:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235057AbhHBOFI (ORCPT ); Mon, 2 Aug 2021 10:05:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:41636 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234711AbhHBN66 (ORCPT ); Mon, 2 Aug 2021 09:58:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DDA6061100; Mon, 2 Aug 2021 13:55:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627912522; bh=qoZEr6d8wVYq/9cZ+ZR4orz12XVv40Z+e7Uyce0nzw8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HUYWeEiVjebsoSPnWO+mZAPabNrt5bmwhQAjUpajqN5wzIzF4fz+jt9OHPtDdm7Bj PaUsqKStOmCU7Zn1j9aG1aKrFrufEcEn0jy7FD/RK3xLcWK+koWvnkFJ+eK3rDzaoL iyeq95nZERHJK808vrL3zNCwO/OxBzdIAEFK3HzU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Begunkov , Jens Axboe Subject: [PATCH 5.13 031/104] io_uring: fix io_prep_async_link locking Date: Mon, 2 Aug 2021 15:44:28 +0200 Message-Id: <20210802134345.042397812@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210802134344.028226640@linuxfoundation.org> References: <20210802134344.028226640@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 commit 44eff40a32e8f5228ae041006352e32638ad2368 upstream. io_prep_async_link() may be called after arming a linked timeout, automatically making it unsafe to traverse the linked list. Guard with completion_lock if there was a linked timeout. Cc: stable@vger.kernel.org # 5.9+ Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/93f7c617e2b4f012a2a175b3dab6bc2f27cebc48.1627304436.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1258,8 +1258,17 @@ static void io_prep_async_link(struct io { struct io_kiocb *cur; - io_for_each_link(cur, req) - io_prep_async_work(cur); + if (req->flags & REQ_F_LINK_TIMEOUT) { + struct io_ring_ctx *ctx = req->ctx; + + spin_lock_irq(&ctx->completion_lock); + io_for_each_link(cur, req) + io_prep_async_work(cur); + spin_unlock_irq(&ctx->completion_lock); + } else { + io_for_each_link(cur, req) + io_prep_async_work(cur); + } } static void io_queue_async_work(struct io_kiocb *req)