[PATCH 2/9] l2tp: WARN_ON rather than BUG_ON in l2tp_dfs_seq_start

[Tom Parkin]

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 <tpar...@katalix.com>
---
 net/l2tp/l2tp_debugfs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c
index 72ba83aa0eaf..96cb9601c21b 100644
--- 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)
-- 
2.17.1