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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 A18BFC04AA7 for ; Mon, 13 May 2019 19:25:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E98720989 for ; Mon, 13 May 2019 19:25:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726982AbfEMTZ5 (ORCPT ); Mon, 13 May 2019 15:25:57 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:46866 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726931AbfEMTZ5 (ORCPT ); Mon, 13 May 2019 15:25:57 -0400 Received: from localhost.localdomain (unknown [IPv6:2804:431:9719:d573:a076:d1fd:3417:b195]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: koike) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id C545F281DC5; Mon, 13 May 2019 20:25:52 +0100 (BST) From: Helen Koike To: dm-devel@redhat.com Cc: kernel@collabora.com, Helen Koike , stable@vger.kernel.org, Mike Snitzer , linux-kernel@vger.kernel.org, Alasdair Kergon Subject: [PATCH] dm ioctl: fix hang in early create error condition Date: Mon, 13 May 2019 16:25:30 -0300 Message-Id: <20190513192530.1167-1-helen.koike@collabora.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The dm_early_create() function (which deals with "dm-mod.create=" kernel command line option) calls dm_hash_insert() who gets an extra reference to the md object. In case of failure, this reference wasn't being released, causing dm_destroy() to hang, thus hanging the whole boot process. Fix this by calling __hash_remove() in the error path. Fixes: 6bbc923dfcf57d ("dm: add support to directly boot to a mapped device") Cc: stable@vger.kernel.org Signed-off-by: Helen Koike --- Hi, I tested this patch by adding a new test case in the following test script: https://gitlab.collabora.com/koike/dm-cmdline-test/commit/d2d7a0ee4a49931cdb59f08a837b516c2d5d743d This test was failing, but with this patch it works correctly. Thanks Helen drivers/md/dm-ioctl.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index c740153b4e52..31da18611a21 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -205,7 +205,8 @@ static void free_cell(struct hash_cell *hc) * The kdev_t and uuid of a device can never change once it is * initially inserted. */ -static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md) +static struct hash_cell *dm_hash_insert(const char *name, const char *uuid, + struct mapped_device *md) { struct hash_cell *cell, *hc; @@ -214,7 +215,7 @@ static int dm_hash_insert(const char *name, const char *uuid, struct mapped_devi */ cell = alloc_cell(name, uuid, md); if (!cell) - return -ENOMEM; + return ERR_PTR(-ENOMEM); /* * Insert the cell into both hash tables. @@ -243,12 +244,12 @@ static int dm_hash_insert(const char *name, const char *uuid, struct mapped_devi mutex_unlock(&dm_hash_cells_mutex); up_write(&_hash_lock); - return 0; + return cell; bad: up_write(&_hash_lock); free_cell(cell); - return -EBUSY; + return ERR_PTR(-EBUSY); } static struct dm_table *__hash_remove(struct hash_cell *hc) @@ -747,6 +748,7 @@ static int dev_create(struct file *filp, struct dm_ioctl *param, size_t param_si { int r, m = DM_ANY_MINOR; struct mapped_device *md; + struct hash_cell *hc; r = check_name(param->name); if (r) @@ -759,11 +761,11 @@ static int dev_create(struct file *filp, struct dm_ioctl *param, size_t param_si if (r) return r; - r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md); - if (r) { + hc = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md); + if (IS_ERR(hc)) { dm_put(md); dm_destroy(md); - return r; + return PTR_ERR(hc); } param->flags &= ~DM_INACTIVE_PRESENT_FLAG; @@ -2044,6 +2046,7 @@ int __init dm_early_create(struct dm_ioctl *dmi, int r, m = DM_ANY_MINOR; struct dm_table *t, *old_map; struct mapped_device *md; + struct hash_cell *hc; unsigned int i; if (!dmi->target_count) @@ -2062,14 +2065,14 @@ int __init dm_early_create(struct dm_ioctl *dmi, return r; /* hash insert */ - r = dm_hash_insert(dmi->name, *dmi->uuid ? dmi->uuid : NULL, md); - if (r) + hc = dm_hash_insert(dmi->name, *dmi->uuid ? dmi->uuid : NULL, md); + if (IS_ERR(hc)) goto err_destroy_dm; /* alloc table */ r = dm_table_create(&t, get_mode(dmi), dmi->target_count, md); if (r) - goto err_destroy_dm; + goto err_hash_remove; /* add targets */ for (i = 0; i < dmi->target_count; i++) { @@ -2116,6 +2119,8 @@ int __init dm_early_create(struct dm_ioctl *dmi, err_destroy_table: dm_table_destroy(t); +err_hash_remove: + __hash_remove(hc); err_destroy_dm: dm_put(md); dm_destroy(md); -- 2.20.1