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 DEB24C43334 for ; Tue, 21 Jun 2022 21:02:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355905AbiFUVCi (ORCPT ); Tue, 21 Jun 2022 17:02:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355902AbiFUU7J (ORCPT ); Tue, 21 Jun 2022 16:59:09 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CBAF3337A; Tue, 21 Jun 2022 13:51:50 -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 3783F61884; Tue, 21 Jun 2022 20:51:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 157ABC36AE2; Tue, 21 Jun 2022 20:51:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655844662; bh=wuwlQqYU2Q0SetwhNRVtAbUs3o+sTJP/YdYjFmeP0nM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nqeQ4QDL5Rj3V5AGssC8Xe4ZSE5xa6ae8sSNndFaL0ifKZ5oDee8L71xB3MR4ZLlW SYhli1JBo0ZyYsIJznUJYdDZifLohn9n8eJOjhau1mRuUxbcRw9BDYXSa6VIdo5OpG CcL11S5fOXBs/i0deXSh/GrCm5LP9JWHskkJiQqBI49P2h0oeZdgHTBCoUNhs63T4S yiNzo8jQjkd6u5mEzC/eNtqOl0P7JIgVLjmKCfdONaqCWmw5hcSSi/ssnS0xBBgXpq zI92O2CfvifSh9FQM7iG4LvZV4btGZzLRpRUReT4wUSBbF6s6iT2hS/g+MV+Y9bFTQ bvra/e9sv1SAw== 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 5.15 15/17] blk-mq: protect q->elevator by ->sysfs_lock in blk_mq_elv_switch_none Date: Tue, 21 Jun 2022 16:50:38 -0400 Message-Id: <20220621205041.250426-15-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220621205041.250426-1-sashal@kernel.org> References: <20220621205041.250426-1-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 b70488e4db94..95da44063e65 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3683,12 +3683,14 @@ 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