| Message ID | 20211207140039.11392-1-alexander.sverdlin@nokia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | nfsd: Fix nsfd startup race (again) | expand |
On Tue, Dec 07, 2021 at 03:00:39PM +0100, Alexander A Sverdlin wrote: > From: Alexander Sverdlin <alexander.sverdlin@nokia.com> > > Commit bd5ae9288d64 ("nfsd: register pernet ops last, unregister first") > has re-opened rpc_pipefs_event() race against nfsd_net_id registration > (register_pernet_subsys()) which has been fixed by commit bb7ffbf29e76 > ("nfsd: fix nsfd startup race triggering BUG_ON"). > > Restore the order of register_pernet_subsys() vs register_cld_notifier(). > Add WARN_ON() to prevent a future regression. That makes sense, thanks. I'll pass it along for 5.16. --b. > > Crash info: > Unable to handle kernel NULL pointer dereference at virtual address 0000000000000012 > CPU: 8 PID: 345 Comm: mount Not tainted 5.4.144-... #1 > pc : rpc_pipefs_event+0x54/0x120 [nfsd] > lr : rpc_pipefs_event+0x48/0x120 [nfsd] > Call trace: > rpc_pipefs_event+0x54/0x120 [nfsd] > blocking_notifier_call_chain > rpc_fill_super > get_tree_keyed > rpc_fs_get_tree > vfs_get_tree > do_mount > ksys_mount > __arm64_sys_mount > el0_svc_handler > el0_svc > > Fixes: bd5ae9288d64 ("nfsd: register pernet ops last, unregister first") > Cc: stable@vger.kernel.org > Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> > --- > fs/nfsd/nfs4recover.c | 1 + > fs/nfsd/nfsctl.c | 14 +++++++------- > 2 files changed, 8 insertions(+), 7 deletions(-) > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c > index 6fedc49..4d829cf 100644 > --- a/fs/nfsd/nfs4recover.c > +++ b/fs/nfsd/nfs4recover.c > @@ -2156,6 +2156,7 @@ static struct notifier_block nfsd4_cld_block = { > int > register_cld_notifier(void) > { > + WARN_ON(!nfsd_net_id); > return rpc_pipefs_notifier_register(&nfsd4_cld_block); > } > > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c > index af8531c..51a49e0 100644 > --- a/fs/nfsd/nfsctl.c > +++ b/fs/nfsd/nfsctl.c > @@ -1521,12 +1521,9 @@ 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 = nfsd4_init_slabs(); > if (retval) > - goto out_unregister_notifier; > + return retval; > retval = nfsd4_init_pnfs(); > if (retval) > goto out_free_slabs; > @@ -1545,9 +1542,14 @@ static int __init init_nfsd(void) > goto out_free_exports; > retval = register_pernet_subsys(&nfsd_net_ops); > if (retval < 0) > + goto out_free_filesystem; > + retval = register_cld_notifier(); > + if (retval) > goto out_free_all; > return 0; > out_free_all: > + unregister_pernet_subsys(&nfsd_net_ops); > +out_free_filesystem: > unregister_filesystem(&nfsd_fs_type); > out_free_exports: > remove_proc_entry("fs/nfs/exports", NULL); > @@ -1561,13 +1563,12 @@ static int __init init_nfsd(void) > nfsd4_exit_pnfs(); > out_free_slabs: > nfsd4_free_slabs(); > -out_unregister_notifier: > - unregister_cld_notifier(); > return retval; > } > > static void __exit exit_nfsd(void) > { > + unregister_cld_notifier(); > unregister_pernet_subsys(&nfsd_net_ops); > nfsd_drc_slab_free(); > remove_proc_entry("fs/nfs/exports", NULL); > @@ -1577,7 +1578,6 @@ static void __exit exit_nfsd(void) > nfsd4_free_slabs(); > nfsd4_exit_pnfs(); > unregister_filesystem(&nfsd_fs_type); > - unregister_cld_notifier(); > } > > MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>"); > -- > 2.10.2
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 6fedc49..4d829cf 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -2156,6 +2156,7 @@ static struct notifier_block nfsd4_cld_block = { int register_cld_notifier(void) { + WARN_ON(!nfsd_net_id); return rpc_pipefs_notifier_register(&nfsd4_cld_block); } diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index af8531c..51a49e0 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1521,12 +1521,9 @@ 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 = nfsd4_init_slabs(); if (retval) - goto out_unregister_notifier; + return retval; retval = nfsd4_init_pnfs(); if (retval) goto out_free_slabs; @@ -1545,9 +1542,14 @@ static int __init init_nfsd(void) goto out_free_exports; retval = register_pernet_subsys(&nfsd_net_ops); if (retval < 0) + goto out_free_filesystem; + retval = register_cld_notifier(); + if (retval) goto out_free_all; return 0; out_free_all: + unregister_pernet_subsys(&nfsd_net_ops); +out_free_filesystem: unregister_filesystem(&nfsd_fs_type); out_free_exports: remove_proc_entry("fs/nfs/exports", NULL); @@ -1561,13 +1563,12 @@ static int __init init_nfsd(void) nfsd4_exit_pnfs(); out_free_slabs: nfsd4_free_slabs(); -out_unregister_notifier: - unregister_cld_notifier(); return retval; } static void __exit exit_nfsd(void) { + unregister_cld_notifier(); unregister_pernet_subsys(&nfsd_net_ops); nfsd_drc_slab_free(); remove_proc_entry("fs/nfs/exports", NULL); @@ -1577,7 +1578,6 @@ static void __exit exit_nfsd(void) nfsd4_free_slabs(); nfsd4_exit_pnfs(); unregister_filesystem(&nfsd_fs_type); - unregister_cld_notifier(); } MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");