[PATCH 4.9 060/164] proc: Fix unbalanced hard link numbers

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@xxxxxxx>

commit d66bb1607e2d8d384e53f3d93db5c18483c8c4f7 upstream.

proc_create_mount_point() forgot to increase the parent's nlink, and
it resulted in unbalanced hard link numbers, e.g. /proc/fs shows one
less than expected.

Fixes: eb6d38d5427b ("proc: Allow creating permanently empty directories...")
Reported-by: Tristan Ye <tristan.ye@xxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/proc/generic.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -471,6 +471,7 @@ struct proc_dir_entry *proc_create_mount
 		ent->data = NULL;
 		ent->proc_fops = NULL;
 		ent->proc_iops = NULL;
+		parent->nlink++;
 		if (proc_register(parent, ent) < 0) {
 			kfree(ent);
 			parent->nlink--;