debugfs: allow bad parent pointers to be passed in

If something went wrong with creating a debugfs file/symlink/directory, that value could be passed down into debugfs again as a parent dentry. To make caller code simpler, just error out if this happens, and don't crash the kernel. Reported-by: Alex Elder <[email protected]> Reviewed-by: Viresh Kumar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Reviewed-by: Alex Elder <[email protected]>
iegor · Apr 3, 2015 · c9e15f2 · c9e15f2
1 parent fdc81b7
commit c9e15f2
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
@@ -254,6 +254,9 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
 
 	pr_debug("debugfs: creating file '%s'\n",name);
 
+	if (IS_ERR(parent))
+		return parent;
+
 	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
 			      &debugfs_mount_count);
 	if (error)