From patchwork Mon Sep 21 16:28:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 309373 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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, 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 BC032C4346B for ; Mon, 21 Sep 2020 16:53:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83CE520874 for ; Mon, 21 Sep 2020 16:53:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600707216; bh=gVPWHHVsRgwOVX6wf9/4LT+JI3nRH5Pmckx3O+v6esA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tHYrVj0gQ8dcmEKvwETR1u2W+uaE/hrPbMIn4f0MXMi0vhMAUVXGa3fOlSoZuIljI KB3Vn/5tpPVPKLRr+PGfWP682d3+WD3si+J6pXF7aHKM9UJaixQWYqaER4BjQYG4gO bpWT7CaZ8O3epgTn9cvqvmSuilp5KyejYw95D3CE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728748AbgIUQrS (ORCPT ); Mon, 21 Sep 2020 12:47:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:54016 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728100AbgIUQrR (ORCPT ); Mon, 21 Sep 2020 12:47:17 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0AE7E2389F; Mon, 21 Sep 2020 16:47:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706836; bh=gVPWHHVsRgwOVX6wf9/4LT+JI3nRH5Pmckx3O+v6esA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y8u6n7LnxusZnG902U6w1b17tnyNJlo4LKMWZeqg7fhpzti5s8RODVWTuZjotm1jM D8kDyxbRIDcKEwSx/o9UrpjhgX4NI+70TquvdNdSRmzflRMuZ6MKUfIdBfMgqBjsEO JXzpm7HxlZYwld7KBUldluhR7LCFahixjV2Sjo3A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Alasdair Kergon , Mike Snitzer , Adrian Huang , Ira Weiny , Dan Williams Subject: [PATCH 5.8 113/118] dm/dax: Fix table reference counts Date: Mon, 21 Sep 2020 18:28:45 +0200 Message-Id: <20200921162041.637820805@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162036.324813383@linuxfoundation.org> References: <20200921162036.324813383@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Dan Williams commit 02186d8897d49b0afd3c80b6cf23437d91024065 upstream. A recent fix to the dm_dax_supported() flow uncovered a latent bug. When dm_get_live_table() fails it is still required to drop the srcu_read_lock(). Without this change the lvm2 test-suite triggers this warning: # lvm2-testsuite --only pvmove-abort-all.sh WARNING: lock held when returning to user space! 5.9.0-rc5+ #251 Tainted: G OE ------------------------------------------------ lvm/1318 is leaving the kernel with locks still held! 1 lock held by lvm/1318: #0: ffff9372abb5a340 (&md->io_barrier){....}-{0:0}, at: dm_get_live_table+0x5/0xb0 [dm_mod] ...and later on this hang signature: INFO: task lvm:1344 blocked for more than 122 seconds. Tainted: G OE 5.9.0-rc5+ #251 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:lvm state:D stack: 0 pid: 1344 ppid: 1 flags:0x00004000 Call Trace: __schedule+0x45f/0xa80 ? finish_task_switch+0x249/0x2c0 ? wait_for_completion+0x86/0x110 schedule+0x5f/0xd0 schedule_timeout+0x212/0x2a0 ? __schedule+0x467/0xa80 ? wait_for_completion+0x86/0x110 wait_for_completion+0xb0/0x110 __synchronize_srcu+0xd1/0x160 ? __bpf_trace_rcu_utilization+0x10/0x10 __dm_suspend+0x6d/0x210 [dm_mod] dm_suspend+0xf6/0x140 [dm_mod] Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices") Cc: Cc: Jan Kara Cc: Alasdair Kergon Cc: Mike Snitzer Reported-by: Adrian Huang Reviewed-by: Ira Weiny Tested-by: Adrian Huang Link: https://lore.kernel.org/r/160045867590.25663.7548541079217827340.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1136,15 +1136,16 @@ static bool dm_dax_supported(struct dax_ { struct mapped_device *md = dax_get_private(dax_dev); struct dm_table *map; + bool ret = false; int srcu_idx; - bool ret; map = dm_get_live_table(md, &srcu_idx); if (!map) - return false; + goto out; ret = dm_table_supports_dax(map, device_supports_dax, &blocksize); +out: dm_put_live_table(md, srcu_idx); return ret;