l2tp: WARN_ON rather than BUG_ON in l2tp_session_queue_purge

l2tp_session_queue_purge is used during session shutdown to drop any
skbs queued for reordering purposes according to L2TP dataplane rules.

The BUG_ON in this function checks the session magic feather in an
attempt to catch lifetime bugs.

Rather than crashing the kernel with a BUG_ON, we can simply WARN_ON and
refuse to do anything more -- in the worst case this could result in a
leak.  However this is highly unlikely given that the session purge only
occurs from codepaths which have obtained the session by means of a lookup
via. the parent tunnel and which check the session "dead" flag to
protect against shutdown races.

While we're here, have l2tp_session_queue_purge return void rather than
an integer, since neither of the callsites checked the return value.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Parkin 2020-07-24 16:31:55 +01:00 committed by David S. Miller
parent ebb4f5e6e4
commit 493048f5df
1 changed files with 4 additions and 3 deletions

View File

@ -773,16 +773,17 @@ EXPORT_SYMBOL(l2tp_recv_common);
/* Drop skbs from the session's reorder_q
*/
static int l2tp_session_queue_purge(struct l2tp_session *session)
static void l2tp_session_queue_purge(struct l2tp_session *session)
{
struct sk_buff *skb = NULL;
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
return;
while ((skb = skb_dequeue(&session->reorder_q))) {
atomic_long_inc(&session->stats.rx_errors);
kfree_skb(skb);
}
return 0;
}
/* Internal UDP receive frame. Do the real work of receiving an L2TP data frame