From 07adfbb3de7529f58ca708a97ead7fa4fdb71056 Mon Sep 17 00:00:00 2001 From: Shuangpeng Bai Date: Fri, 17 Jul 2026 13:28:09 -0400 Subject: [PATCH] lockd: fix NULL dereference on lockowner allocation failure commit 4c7fc129db061c7daab841c4f3c342d894832362 upstream. nlmclnt_locks_init_private() installs NLM file lock operations even when nlmclnt_find_lockowner() fails to allocate a lockowner. nlmclnt_proc() then returns -ENOMEM, but the VFS still tears down the partially initialized file_lock and calls locks_release_private(). That invokes nlmclnt_locks_release_private(), which dereferences fl->fl_u.nfs_fl.owner and crashes because the owner was never installed. Clear fl_ops before attempting to initialize the NLM private state, and install the NLM lock operations only after a lockowner has been allocated successfully. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Shuangpeng Bai Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/lockd/clntproc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c index cebcc283b7ce..8728b53cf2e8 100644 --- a/fs/lockd/clntproc.c +++ b/fs/lockd/clntproc.c @@ -487,9 +487,12 @@ static const struct file_lock_operations nlmclnt_lock_ops = { static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host) { fl->fl_u.nfs_fl.state = 0; + fl->fl_ops = NULL; fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host, fl->c.flc_owner); INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list); + if (!fl->fl_u.nfs_fl.owner) + return; fl->fl_ops = &nlmclnt_lock_ops; }