From patchwork Wed Apr 16 04:03:36 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 3997521 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id AD2CD9F2BA for ; Wed, 16 Apr 2014 04:22:19 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E9A4D2021A for ; Wed, 16 Apr 2014 04:22:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B91B20200 for ; Wed, 16 Apr 2014 04:22:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754140AbaDPETd (ORCPT ); Wed, 16 Apr 2014 00:19:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38854 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbaDPETa (ORCPT ); Wed, 16 Apr 2014 00:19:30 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 8BB48AB0E; Wed, 16 Apr 2014 04:19:29 +0000 (UTC) From: NeilBrown To: linux-mm@kvack.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 16 Apr 2014 14:03:36 +1000 Subject: [PATCH 14/19] driver core: set PF_FSTRANS while holding gdp_mutex Cc: xfs@oss.sgi.com Message-ID: <20140416040336.10604.223.stgit@notabene.brown> In-Reply-To: <20140416033623.10604.69237.stgit@notabene.brown> References: <20140416033623.10604.69237.stgit@notabene.brown> User-Agent: StGit/0.16 MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP lockdep reports a locking chain: sk_lock-AF_INET --> rtnl_mutex --> gdp_mutex As sk_lock can be needed for memory reclaim (when loop-back NFS is in use at least), any memory allocation under gdp_mutex needs to be protected by PF_FSTRANS. The path frome rtnl_mutex to gdp_mutex is [] get_device_parent+0x4c/0x1f0 [] device_add+0xe6/0x610 [] netdev_register_kobject+0x7a/0x130 [] register_netdevice+0x354/0x550 [] register_netdev+0x15/0x30 Signed-off-by: NeilBrown --- drivers/base/core.c | 3 +++ 1 file changed, 3 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/base/core.c b/drivers/base/core.c index 2b567177ef78..1a2735237650 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -750,6 +750,7 @@ static struct kobject *get_device_parent(struct device *dev, struct kobject *kobj = NULL; struct kobject *parent_kobj; struct kobject *k; + unsigned int pflags; #ifdef CONFIG_BLOCK /* block disks show up in /sys/block */ @@ -788,7 +789,9 @@ static struct kobject *get_device_parent(struct device *dev, } /* or create a new class-directory at the parent device */ + current_set_flags_nested(&pflags, PF_FSTRANS); k = class_dir_create_and_add(dev->class, parent_kobj); + current_restore_flags_nested(&pflags, PF_FSTRANS); /* do not emit an uevent for this simple "glue" directory */ mutex_unlock(&gdp_mutex); return k;