From d5d30089c2a59d079a074eb37c8c223b81664ceb Mon Sep 17 00:00:00 2001 From: Giuseppe Cantavenera Date: Mon, 20 Apr 2015 18:00:08 +0200 Subject: nfsd: fix nsfd startup race triggering BUG_ON 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 Signed-off-by: Greg Kroah-Hartman --- 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 aa47d75ddb26..9690cb4dd588 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1250,15 +1250,15 @@ 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 = nfsd4_init_pnfs(); if (retval) goto out_free_slabs; @@ -1290,10 +1290,10 @@ out_exit_pnfs: nfsd4_exit_pnfs(); 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; } @@ -1308,8 +1308,8 @@ static void __exit exit_nfsd(void) nfsd4_exit_pnfs(); 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 "); -- cgit v1.2.3