l2tp: WARN_ON rather than BUG_ON in l2tp_dfs_seq_start

l2tp_dfs_seq_start had a BUG_ON to catch a possible programming error in
l2tp_dfs_seq_open.

Since we can easily bail out of l2tp_dfs_seq_start, prefer to do that
and flag the error with a WARN_ON rather than crashing the kernel.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c
index 72ba83a..96cb960 100644 (file)
--- a/net/l2tp/l2tp_debugfs.c
+++ b/net/l2tp/l2tp_debugfs.c
@@ -72,7 +72,10 @@ static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
        if (!pos)
                goto out;
 
-       BUG_ON(!m->private);
+       if (WARN_ON(!m->private)) {
+               pd = NULL;
+               goto out;
+       }
        pd = m->private;
 
        if (!pd->tunnel)