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 02EFEC43334 for ; Tue, 21 Jun 2022 21:09:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355264AbiFUVJz (ORCPT ); Tue, 21 Jun 2022 17:09:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356942AbiFUVJT (ORCPT ); Tue, 21 Jun 2022 17:09:19 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7BB2438185; Tue, 21 Jun 2022 13:56:41 -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 ams.source.kernel.org (Postfix) with ESMTPS id 6C571B81B44; Tue, 21 Jun 2022 20:51:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B59FC36AE2; Tue, 21 Jun 2022 20:51:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655844698; bh=DuCmFgxmSIYfUmNeEAstZzRTUN8BuWqdirZKFOoed8Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gSF2jaEZ0+AKFv5apLozRR7NPEfyBvOaLbppeeuNytJrZuI6GjtBRAs1kLt8cXp84 km4rVeSeH3E+kCMYX8wg5TNH6EQRZ5/hjzCcYfTqtyMXTBPeKNEPMYfSfc7obS1jwh eEm6jMApNdeMRkSUir90ztZ4DlK4IBXRg272V764MN6ZylaMB1d3Xqyiz1i4WkGmmT 6tWe8dTlbZ5+oHVLutbWVSmWlZPtGM/C9x80oT0eDV8h/PB7/f103XqtIv/Dsg4vWh TzHDCIOoApire1RVDKiPmXTvrVTPy8JP+qgeV3ba+DvcigrPMF1DYzWZDkRGSHfugl vPdoahmROhvrw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ming Lei , Christoph Hellwig , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 6/7] blk-mq: protect q->elevator by ->sysfs_lock in blk_mq_elv_switch_none Date: Tue, 21 Jun 2022 16:51:28 -0400 Message-Id: <20220621205130.250874-6-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220621205130.250874-1-sashal@kernel.org> References: <20220621205130.250874-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ming Lei [ Upstream commit 5fd7a84a09e640016fe106dd3e992f5210e23dc7 ] elevator can be tore down by sysfs switch interface or disk release, so hold ->sysfs_lock before referring to q->elevator, then potential use-after-free can be avoided. Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20220616014401.817001-2-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-mq.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index ae70b4809bec..3a791597c534 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2940,12 +2940,14 @@ static bool blk_mq_elv_switch_none(struct list_head *head, if (!qe) return false; + /* q->elevator needs protection from ->sysfs_lock */ + mutex_lock(&q->sysfs_lock); + INIT_LIST_HEAD(&qe->node); qe->q = q; qe->type = q->elevator->type; list_add(&qe->node, head); - mutex_lock(&q->sysfs_lock); /* * After elevator_switch_mq, the previous elevator_queue will be * released by elevator_release. The reference of the io scheduler -- 2.35.1