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 CAC87CCA48D for ; Tue, 21 Jun 2022 21:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356606AbiFUVEg (ORCPT ); Tue, 21 Jun 2022 17:04:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355345AbiFUVBD (ORCPT ); Tue, 21 Jun 2022 17:01:03 -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 05A6D18E0E; Tue, 21 Jun 2022 13:53:00 -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 3F78BB81B2E; Tue, 21 Jun 2022 20:51:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 781BCC341C5; Tue, 21 Jun 2022 20:51:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655844688; bh=y/YKOVyGTJLYeT7AKWF3q0TQrnWzUX01HdNS9l3D26s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KiB8yxJmhNMAvLwosgnnds7jOQ1jRd7WkXXQIZDyO0/jvXeoXvO7Jgoiffagblpqj Da2GrlT3o4v2SKt9FAK032hBVPvCo2hHy86VUH5qcWtUEa6XH1K+GvCx4BGVWDszN6 UCu4ZpigECq4MPKHpStrvsfMo6SKLfLTYtZAIiB0R9wjVIWZxuSwy79257psOWYXv3 NgfppXECRYLMDf+Nc4H7OQQevm17F9j6DLHAhYkYqpHfOdtLQ2HRMDIROcQjZpKj1e eMXDoTdHSv2TmsPcbmLFIAJSYn4n1zMY7OFtpuYEbPuxsFHoJwZh4+JDXHxSYrTbk/ YbJxWRAljybCQ== 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 5.4 6/7] blk-mq: protect q->elevator by ->sysfs_lock in blk_mq_elv_switch_none Date: Tue, 21 Jun 2022 16:51:18 -0400 Message-Id: <20220621205120.250779-6-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220621205120.250779-1-sashal@kernel.org> References: <20220621205120.250779-1-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 84798d09ca46..959df4e60f4e 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3247,12 +3247,14 @@ 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