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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01AAFC3A59F for ; Thu, 29 Aug 2019 18:29:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4A7A205C9 for ; Thu, 29 Aug 2019 18:29:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567103354; bh=kCo6rtnN3uj+HRkVKB54selVGg42JXeQR2KTGbXdhjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=grYiAlaVCQjeFoPgMUZGwctLBeDYYD7gg6HS1XnluEXgi3Q2UYoym0aitJHZYymB+ 0qF4lnP242Mo03ujx+1DfKp97CJZ2WGVcavTKiqFhnR5b9b99xrvuGveYAnQDXPL+y j3e2M9N9KIRa2QXtjOQYsrKYMI6XqpBlkfkFxu3o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729982AbfH2S3N (ORCPT ); Thu, 29 Aug 2019 14:29:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:56778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729055AbfH2SPG (ORCPT ); Thu, 29 Aug 2019 14:15:06 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 27D2E23404; Thu, 29 Aug 2019 18:15:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567102506; bh=kCo6rtnN3uj+HRkVKB54selVGg42JXeQR2KTGbXdhjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=am750hGKWqVrVOhuAO9brEHIGWEjdqh2tg+xQMeAoMKjGjSdRHU/uBYB6eOcKFtg5 pPmYC85rNYYwM1pdym3jHrAmeceM7rFHwG7d1+7g1gaFUns9hlTKOuaQG2Rj9nqEco 5YKq6uxFzX+oM6hg/mSECmIY8uxaog/XysxmAyco= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Anton Eidelman , Christoph Hellwig , Sagi Grimberg , Jens Axboe , Sasha Levin , linux-nvme@lists.infradead.org Subject: [PATCH AUTOSEL 5.2 56/76] nvme-multipath: fix possible I/O hang when paths are updated Date: Thu, 29 Aug 2019 14:12:51 -0400 Message-Id: <20190829181311.7562-56-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190829181311.7562-1-sashal@kernel.org> References: <20190829181311.7562-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anton Eidelman [ Upstream commit 504db087aaccdb32af61539916409f7dca31ceb5 ] nvme_state_set_live() making a path available triggers requeue_work in order to resubmit requests that ended up on requeue_list when no paths were available. This requeue_work may race with concurrent nvme_ns_head_make_request() that do not observe the live path yet. Such concurrent requests may by made by either: - New IO submission. - Requeue_work triggered by nvme_failover_req() or another ana_work. A race may cause requeue_work capture the state of requeue_list before more requests get onto the list. These requests will stay on the list forever unless requeue_work is triggered again. In order to prevent such race, nvme_state_set_live() should synchronize_srcu(&head->srcu) before triggering the requeue_work and prevent nvme_ns_head_make_request referencing an old snapshot of the path list. Reviewed-by: Christoph Hellwig Signed-off-by: Anton Eidelman Signed-off-by: Sagi Grimberg Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/nvme/host/multipath.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index e942b3e840687..4f599366bc5ae 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -356,6 +356,7 @@ static void nvme_mpath_set_live(struct nvme_ns *ns) srcu_read_unlock(&head->srcu, srcu_idx); } + synchronize_srcu(&ns->head->srcu); kblockd_schedule_work(&ns->head->requeue_work); } -- 2.20.1