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 78792C4167B for ; Mon, 27 Nov 2023 18:07:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232369AbjK0SHL (ORCPT ); Mon, 27 Nov 2023 13:07:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230293AbjK0SHI (ORCPT ); Mon, 27 Nov 2023 13:07:08 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA005191 for ; Mon, 27 Nov 2023 10:07:15 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D53BDC433C7; Mon, 27 Nov 2023 18:07:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701108435; bh=C3iVJwmeksjG1jAgFK6vw2pYVe/zJA3lIfqMl4WWsac=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fx2QF6SBm6idjn5TdulasO2joS/StL0OvmHxjqPckG9XbaDVKVQqLguxJ+olvY9fp ACMHcwPPgjcKunryqyL9FtMNaOBb7xdAIRGon4eElaOX8Wxy63hBHFUB59+NXRjUyt FL1l8BeDv907J+DzcvkrXFbWYeBc/0r6B4uYGno7EmzHMdX9ID3JJKWWm29+w2L3Ms amjd+gzzB1JeYYEHBbzZg2OtWWizp6kalTUrh4Pa1HxKZiiTt/hKcqI3x17EMFBDMY PTSVVm5b4at1yVXypqNr584qNxZRzsZaJAIU3u48Slb40iAqbUPch4eLPHGr/JWCPn rS4hrjKDnJ7Kw== Date: Mon, 27 Nov 2023 11:07:12 -0700 From: Keith Busch To: Bitao Hu Cc: axboe@kernel.dk, hch@lst.de, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, kanie@linux.alibaba.com Subject: Re: [PATCH] nvme: fix deadlock between reset and scan Message-ID: References: <1700737213-110685-1-git-send-email-yaoma@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1700737213-110685-1-git-send-email-yaoma@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 23, 2023 at 07:00:13PM +0800, Bitao Hu wrote: > @@ -3631,6 +3631,11 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info) > goto out_unlink_ns; > > down_write(&ctrl->namespaces_rwsem); > + /* preventing adding ns during resetting */ > + if (unlikely(ctrl->state != NVME_CTRL_LIVE)) { We can't rely on ctrl->state for preventing deadlocks. Reading unlocked ctrl->state is often used, but should be considered advisory-only since the state could change immediatly after reading it. > + up_write(&ctrl->namespaces_rwsem); > + goto out_unlink_ns; > + } > nvme_ns_add_to_ctrl_list(ns); > up_write(&ctrl->namespaces_rwsem); > nvme_get_ctrl(ctrl);