5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Antipov <dmantipov@xxxxxxxxx> [ Upstream commit a8c695005bfe6569acd73d777ca298ddddd66105 ] Since j1939_session_skb_queue() does an extra skb_get() for each new skb, do the same for the initial one in j1939_session_new() to avoid refcount underflow. Reported-by: syzbot+d4e8dc385d9258220c31@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=d4e8dc385d9258220c31 Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Dmitry Antipov <dmantipov@xxxxxxxxx> Tested-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> Link: https://patch.msgid.link/20241105094823.2403806-1-dmantipov@xxxxxxxxx [mkl: clean up commit message] Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/can/j1939/transport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index 5d2097e5ca3a8..a58f6f5dfcf8e 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -1505,7 +1505,7 @@ static struct j1939_session *j1939_session_new(struct j1939_priv *priv, session->state = J1939_SESSION_NEW; skb_queue_head_init(&session->skb_queue); - skb_queue_tail(&session->skb_queue, skb); + skb_queue_tail(&session->skb_queue, skb_get(skb)); skcb = j1939_skb_to_cb(skb); memcpy(&session->skcb, skcb, sizeof(session->skcb)); -- 2.43.0
