From patchwork Mon Sep 21 16:31:48 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: 263645 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 DD5D5C43468 for ; Mon, 21 Sep 2020 16:51:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACC2F2076E for ; Mon, 21 Sep 2020 16:51:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600707113; bh=vFRjhdIAoRFwKh1ae3jf1pvUmi3RbcGPaf/Hy5Viby4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gcupY0JnHWLsoLQ/TjxhMQJb57RHA3iOkMb2FV5Aszja5oM/BdJY6etlOamr5w3Uu oh+m36Va6BW7d7jW06ADgsXGrcUsO1WPkr8qD721Bdl4JIQXUlqy7EQbGczSiry8wp i+TJl+9giYCJlzv1e13BazO+xxynfqk+x2B/Sg6Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729594AbgIUQu3 (ORCPT ); Mon, 21 Sep 2020 12:50:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:58930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728437AbgIUQu2 (ORCPT ); Mon, 21 Sep 2020 12:50:28 -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 66086238A1; Mon, 21 Sep 2020 16:50:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600707027; bh=vFRjhdIAoRFwKh1ae3jf1pvUmi3RbcGPaf/Hy5Viby4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PFx2+RrolejYuvGrQyNWV9LspFQy60M1a82iKFQXcWIZyTKB9yM8Jb6NdD5zIZzh3 m6534+6WsP5JIGYq48dScBOnohAfRT5pxtH4xy+oyj1utcNMItHsNlMOEmaJI7PPdm 1WyK7/000gNCLgnR3wTSOBobLd9iFxlP7f/nd88M= 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 5.4 69/72] dm/dax: Fix table reference counts Date: Mon, 21 Sep 2020 18:31:48 +0200 Message-Id: <20200921163125.144112382@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921163121.870386357@linuxfoundation.org> References: <20200921163121.870386357@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 @@ -1112,15 +1112,16 @@ 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;