From 1aa646ac71feb987a9571e1d70980d10ff495fbc Mon Sep 17 00:00:00 2001 From: Tom Parkin Date: Fri, 24 Jul 2020 16:31:53 +0100 Subject: l2tp: don't BUG_ON session magic checks in l2tp_ppp checkpatch advises that WARN_ON and recovery code are preferred over BUG_ON which crashes the kernel. l2tp_ppp.c's BUG_ON checks of the l2tp session structure's "magic" field occur in code paths where it's reasonably easy to recover: * In the case of pppol2tp_sock_to_session, we can return NULL and the caller will bail out appropriately. There is no change required to any of the callsites of this function since they already handle pppol2tp_sock_to_session returning NULL. * In the case of pppol2tp_session_destruct we can just avoid decrementing the reference count on the suspect session structure. In the worst case scenario this results in a memory leak, which is preferable to a crash. Convert these uses of BUG_ON to WARN_ON accordingly. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller --- net/l2tp/l2tp_ppp.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'net/l2tp/l2tp_ppp.c') diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 4389df66af35..2aeee648c080 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -163,8 +163,11 @@ static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk) sock_put(sk); goto out; } - - BUG_ON(session->magic != L2TP_SESSION_MAGIC); + if (WARN_ON(session->magic != L2TP_SESSION_MAGIC)) { + session = NULL; + sock_put(sk); + goto out; + } out: return session; @@ -419,7 +422,8 @@ static void pppol2tp_session_destruct(struct sock *sk) if (session) { sk->sk_user_data = NULL; - BUG_ON(session->magic != L2TP_SESSION_MAGIC); + if (WARN_ON(session->magic != L2TP_SESSION_MAGIC)) + return; l2tp_session_dec_refcount(session); } } -- cgit v1.2.3-59-g8ed1b