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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81DCDC433EF for ; Tue, 12 Apr 2022 06:50:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349482AbiDLGwX (ORCPT ); Tue, 12 Apr 2022 02:52:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350875AbiDLGsP (ORCPT ); Tue, 12 Apr 2022 02:48:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72DFC25585; Mon, 11 Apr 2022 23:39:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id CF190618DC; Tue, 12 Apr 2022 06:39:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBE36C385A1; Tue, 12 Apr 2022 06:39:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649745569; bh=596DBPnwHs2YqO+iTvAQw1ZottEYdxgsk57woNRTF7A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NA2zMNMSys+VeIeeJM/qlQeQqwPuOd3i8yl1qnesX4AaFzgVUiHhP6uJKv71CKTsm 2vFNoipSFL3ihq4Y1n4ozkDWc4/Wy0ngurS6sYMS3bg0X5krHwWffi5RqG5/2I3YIE RKfN5iePaE9wnZjDIMRpmbJjN3q0HzdJTsg2bg3I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jens Axboe Subject: [PATCH 5.10 141/171] io_uring: fix race between timeout flush and removal Date: Tue, 12 Apr 2022 08:30:32 +0200 Message-Id: <20220412062931.969405079@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062927.870347203@linuxfoundation.org> References: <20220412062927.870347203@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: Jens Axboe commit e677edbcabee849bfdd43f1602bccbecf736a646 upstream. io_flush_timeouts() assumes the timeout isn't in progress of triggering or being removed/canceled, so it unconditionally removes it from the timeout list and attempts to cancel it. Leave it on the list and let the normal timeout cancelation take care of it. Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1556,6 +1556,7 @@ static void __io_queue_deferred(struct i static void io_flush_timeouts(struct io_ring_ctx *ctx) { + struct io_kiocb *req, *tmp; u32 seq; if (list_empty(&ctx->timeout_list)) @@ -1563,10 +1564,8 @@ static void io_flush_timeouts(struct io_ seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); - do { + list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) { u32 events_needed, events_got; - struct io_kiocb *req = list_first_entry(&ctx->timeout_list, - struct io_kiocb, timeout.list); if (io_is_timeout_noseq(req)) break; @@ -1583,9 +1582,8 @@ static void io_flush_timeouts(struct io_ if (events_got < events_needed) break; - list_del_init(&req->timeout.list); io_kill_timeout(req, 0); - } while (!list_empty(&ctx->timeout_list)); + } ctx->cq_last_tm_flush = seq; } @@ -5639,6 +5637,7 @@ static int io_timeout_prep(struct io_kio else data->mode = HRTIMER_MODE_REL; + INIT_LIST_HEAD(&req->timeout.list); hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode); return 0; } @@ -6282,12 +6281,12 @@ static enum hrtimer_restart io_link_time if (!list_empty(&req->link_list)) { prev = list_entry(req->link_list.prev, struct io_kiocb, link_list); - if (refcount_inc_not_zero(&prev->refs)) - list_del_init(&req->link_list); - else + list_del_init(&req->link_list); + if (!refcount_inc_not_zero(&prev->refs)) prev = NULL; } + list_del(&req->timeout.list); spin_unlock_irqrestore(&ctx->completion_lock, flags); if (prev) {