nfsd: fix panic in posix_unblock_lock called from nfs4_laundromat

From kernel 4.9, my two nfsv4 servers sometimes suffer from
    "panic: unable to handle kernel page request"
in posix_unblock_lock() called from nfs4_laundromat().

These panics diseappear if we revert the commit "nfsd: add a LRU list
for blocked locks".

The cause appears to be a typo in nfs4_laundromat(), which is also
present in nfs4_state_shutdown_net().

Cc: stable@vger.kernel.org
Fixes: 7919d0a27f1e "nfsd: add a LRU list for blocked locks"
Cc: jlayton@redhat.com
Reveiwed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 98342d262771..d0992d59f4e1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4790,7 +4790,7 @@ nfs4_laundromat(struct nfsd_net *nn)
         spin_unlock(&nn->blocked_locks_lock);
 
         while (!list_empty(&reaplist)) {
-                nbl = list_first_entry(&nn->blocked_locks_lru,
+                nbl = list_first_entry(&reaplist,
                                         struct nfsd4_blocked_lock, nbl_lru);
                 list_del_init(&nbl->nbl_lru);
                 posix_unblock_lock(&nbl->nbl_lock);
@@ -7236,7 +7236,7 @@ nfs4_state_shutdown_net(struct net *net)
         spin_unlock(&nn->blocked_locks_lock);
 
         while (!list_empty(&reaplist)) {
-                nbl = list_first_entry(&nn->blocked_locks_lru,
+                nbl = list_first_entry(&reaplist,
                                         struct nfsd4_blocked_lock, nbl_lru);
                 list_del_init(&nbl->nbl_lru);
                 posix_unblock_lock(&nbl->nbl_lock);