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 4CE02C433EF for ; Mon, 21 Feb 2022 09:13:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236528AbiBUJOB (ORCPT ); Mon, 21 Feb 2022 04:14:01 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:36076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348123AbiBUJLA (ORCPT ); Mon, 21 Feb 2022 04:11:00 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5F4C1EEDD; Mon, 21 Feb 2022 01:02:51 -0800 (PST) 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 8F62CB80EB5; Mon, 21 Feb 2022 09:02:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1064C340E9; Mon, 21 Feb 2022 09:02:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1645434169; bh=25qGAk3OMopHHcAoP54ETaPWw5tGE/HxiBNZo81UwnE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kPfPF+AAju2AIY4WkcVq3UIodDoIPvBlVuGVcG/UpoF5okOO7nI6LbGky+d8xlydk aoVUQluTf7SdLA79844K1G6/vkeZBjyVotAhlCILKjH+NOGHXzkDFQIH5VZJpq6bKt B+TVotlJYJ8UMoNPpVE0i7yOgny3JsZHW6B7fLJs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sagi Grimberg , Sasha Levin Subject: [PATCH 5.10 037/121] nvme: fix a possible use-after-free in controller reset during load Date: Mon, 21 Feb 2022 09:48:49 +0100 Message-Id: <20220221084922.446771367@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221084921.147454846@linuxfoundation.org> References: <20220221084921.147454846@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: stable@vger.kernel.org From: Sagi Grimberg [ Upstream commit 0fa0f99fc84e41057cbdd2efbfe91c6b2f47dd9d ] Unlike .queue_rq, in .submit_async_event drivers may not check the ctrl readiness for AER submission. This may lead to a use-after-free condition that was observed with nvme-tcp. The race condition may happen in the following scenario: 1. driver executes its reset_ctrl_work 2. -> nvme_stop_ctrl - flushes ctrl async_event_work 3. ctrl sends AEN which is received by the host, which in turn schedules AEN handling 4. teardown admin queue (which releases the queue socket) 5. AEN processed, submits another AER, calling the driver to submit 6. driver attempts to send the cmd ==> use-after-free In order to fix that, add ctrl state check to validate the ctrl is actually able to accept the AER submission. This addresses the above race in controller resets because the driver during teardown should: 1. change ctrl state to RESETTING 2. flush async_event_work (as well as other async work elements) So after 1,2, any other AER command will find the ctrl state to be RESETTING and bail out without submitting the AER. Signed-off-by: Sagi Grimberg Signed-off-by: Sasha Levin --- drivers/nvme/host/core.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 99b5152482fe4..71c85c99e86c6 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -4259,7 +4259,14 @@ static void nvme_async_event_work(struct work_struct *work) container_of(work, struct nvme_ctrl, async_event_work); nvme_aen_uevent(ctrl); - ctrl->ops->submit_async_event(ctrl); + + /* + * The transport drivers must guarantee AER submission here is safe by + * flushing ctrl async_event_work after changing the controller state + * from LIVE and before freeing the admin queue. + */ + if (ctrl->state == NVME_CTRL_LIVE) + ctrl->ops->submit_async_event(ctrl); } static bool nvme_ctrl_pp_status(struct nvme_ctrl *ctrl) -- 2.34.1