From patchwork Mon Feb 21 08:47:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 544743 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 D473EC43217 for ; Mon, 21 Feb 2022 09:48:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351289AbiBUJsu (ORCPT ); Mon, 21 Feb 2022 04:48:50 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:42726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352145AbiBUJrL (ORCPT ); Mon, 21 Feb 2022 04:47:11 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54FAC40E72; Mon, 21 Feb 2022 01:19:06 -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 dfw.source.kernel.org (Postfix) with ESMTPS id E4AA260F4E; Mon, 21 Feb 2022 09:19:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5DCFC340E9; Mon, 21 Feb 2022 09:19:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1645435145; bh=oaexEo1n/fmSwflUo0Lwc/rDGF0py2hBb4yzWuhSC9c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NxQ/hxrDTRsrVIMRmqT2mx9LOtuRHanvkFKxBCs5na0oMKLrVyWZhGWLZFsCQofg7 ulAZGKvoRmMY616E6a3Au12iNvVi8BN1S+JcPrVDBMHiH1k5npSkjO5zQpP12nQj6v otmXAsE5TEF08AqrwE5bZfhFI0a4OgqbDb5Id6P0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sagi Grimberg , Sasha Levin Subject: [PATCH 5.16 060/227] nvme: fix a possible use-after-free in controller reset during load Date: Mon, 21 Feb 2022 09:47:59 +0100 Message-Id: <20220221084936.873953605@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221084934.836145070@linuxfoundation.org> References: <20220221084934.836145070@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 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 1af8a4513708a..9a6586c69afe8 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -4258,7 +4258,14 @@ 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)