From patchwork Tue Aug 10 17:30:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 495126 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=-19.5 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=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 064C4C4338F for ; Tue, 10 Aug 2021 17:32:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E06F66108F for ; Tue, 10 Aug 2021 17:32:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231241AbhHJRcb (ORCPT ); Tue, 10 Aug 2021 13:32:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:60414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231378AbhHJRcZ (ORCPT ); Tue, 10 Aug 2021 13:32:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C797D60EBD; Tue, 10 Aug 2021 17:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1628616723; bh=PShQlVGMPaAenVHYXxAYxeX2uPj4ZEzFUew4cTnd/ZI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=snMiXVpxDJE7xg8Dx2bKeVpfNsiM+euIU6zsAbPL6vUsIw/utvTPtQKSWtak5LqVk rZott3itUZVexCEzM8tW5fSvrh1FPyCQGUbpuzqCFVpGEa2xXL2pv3motxXW+jzUpg V9c5Yt8S04Uk0HobGHHUKJ7hmEkJRESgkx+9bpDU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yu Kuai , Tejun Heo , Jens Axboe , Sasha Levin Subject: [PATCH 4.19 19/54] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() Date: Tue, 10 Aug 2021 19:30:13 +0200 Message-Id: <20210810172944.811282415@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210810172944.179901509@linuxfoundation.org> References: <20210810172944.179901509@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yu Kuai [ Upstream commit 8d75d0eff6887bcac7225e12b9c75595e523d92d ] If queue is dying while iolatency_set_limit() is in progress, blk_get_queue() won't increment the refcount of the queue. However, blk_put_queue() will still decrement the refcount later, which will cause the refcout to be unbalanced. Thus error out in such case to fix the problem. Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter") Signed-off-by: Yu Kuai Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20210805124645.543797-1-yukuai3@huawei.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-iolatency.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index 0529e94a20f7..019cf002ecee 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -800,7 +800,11 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf, enable = iolatency_set_min_lat_nsec(blkg, lat_val); if (enable) { - WARN_ON_ONCE(!blk_get_queue(blkg->q)); + if (!blk_get_queue(blkg->q)) { + ret = -ENODEV; + goto out; + } + blkg_get(blkg); }