From patchwork Thu May 7 09:45:48 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 469520 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id B27EA140218; Thu, 7 May 2015 19:54:52 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1YqIW0-0003Cm-J2; Thu, 07 May 2015 09:54:48 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1YqIR6-00083y-Iu for kernel-team@lists.ubuntu.com; Thu, 07 May 2015 09:49:44 +0000 Received: from av-217-129-142-138.netvisao.pt ([217.129.142.138] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1YqIR6-0002RS-5N; Thu, 07 May 2015 09:49:44 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.16.y-ckt 139/180] nfsd: fix nsfd startup race triggering BUG_ON Date: Thu, 7 May 2015 10:45:48 +0100 Message-Id: <1430991989-23170-140-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1430991989-23170-1-git-send-email-luis.henriques@canonical.com> References: <1430991989-23170-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Cc: Giuseppe Cantavenera , "J. Bruce Fields" , Lorenzo Restelli X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.16.7-ckt11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Giuseppe Cantavenera commit bb7ffbf29e76b89a86ca4c3ee0d4690641f2f772 upstream. nfsd triggered a BUG_ON in net_generic(...) when rpc_pipefs_event(...) in fs/nfsd/nfs4recover.c was called before assigning ntfsd_net_id. The following was observed on a MIPS 32-core processor: kernel: Call Trace: kernel: [] rpc_pipefs_event+0x7c/0x158 [nfsd] kernel: [] notifier_call_chain+0x70/0xb8 kernel: [] __blocking_notifier_call_chain+0x4c/0x70 kernel: [] rpc_fill_super+0xf8/0x1a0 kernel: [] mount_ns+0xb4/0xf0 kernel: [] mount_fs+0x50/0x1f8 kernel: [] vfs_kern_mount+0x58/0xf0 kernel: [] do_mount+0x27c/0xa28 kernel: [] SyS_mount+0x98/0xe8 kernel: [] handle_sys64+0x44/0x68 kernel: kernel: Code: 0040f809 00000000 2e020001 <00020336> 3c12c00d 3c02801a de100000 6442eb98 0040f809 kernel: ---[ end trace 7471374335809536 ]--- Fixed this behaviour by calling register_pernet_subsys(&nfsd_net_ops) before registering rpc_pipefs_event(...) with the notifier chain. Signed-off-by: Giuseppe Cantavenera Signed-off-by: Lorenzo Restelli Reviewed-by: Kinlong Mee Signed-off-by: J. Bruce Fields [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques --- fs/nfsd/nfsctl.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 51844048937f..1f451f90f857 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1170,15 +1170,15 @@ static int __init init_nfsd(void) int retval; printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n"); - retval = register_cld_notifier(); - if (retval) - return retval; retval = register_pernet_subsys(&nfsd_net_ops); if (retval < 0) - goto out_unregister_notifier; - retval = nfsd4_init_slabs(); + return retval; + retval = register_cld_notifier(); if (retval) goto out_unregister_pernet; + retval = nfsd4_init_slabs(); + if (retval) + goto out_unregister_notifier; retval = nfsd_fault_inject_init(); /* nfsd fault injection controls */ if (retval) goto out_free_slabs; @@ -1205,10 +1205,10 @@ out_free_stat: nfsd_fault_inject_cleanup(); out_free_slabs: nfsd4_free_slabs(); -out_unregister_pernet: - unregister_pernet_subsys(&nfsd_net_ops); out_unregister_notifier: unregister_cld_notifier(); +out_unregister_pernet: + unregister_pernet_subsys(&nfsd_net_ops); return retval; } @@ -1222,8 +1222,8 @@ static void __exit exit_nfsd(void) nfsd4_free_slabs(); nfsd_fault_inject_cleanup(); unregister_filesystem(&nfsd_fs_type); - unregister_pernet_subsys(&nfsd_net_ops); unregister_cld_notifier(); + unregister_pernet_subsys(&nfsd_net_ops); } MODULE_AUTHOR("Olaf Kirch ");