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| author | Alexander Sverdlin <alexander.sverdlin@nokia.com> | 2021-12-07 15:00:39 +0100 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2021-12-10 17:54:59 +0100 |
| commit | b10252c7ae9c9d7c90552f88b544a44ee773af64 (patch) | |
| tree | eb69e5e677f47ae4e1af278ad871508935fe1e7b /fs/nfsd/nfs4recover.c | |
| parent | Linux 5.16-rc4 (diff) | |
| download | linux-b10252c7ae9c9d7c90552f88b544a44ee773af64.tar.xz linux-b10252c7ae9c9d7c90552f88b544a44ee773af64.zip | |
nfsd: Fix nsfd startup race (again)
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.
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>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd/nfs4recover.c')
| -rw-r--r-- | fs/nfsd/nfs4recover.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 6fedc49726bf..c634483d85d2 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); } |