5.4-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Antipov dmantipov@yandex.ru
[ 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@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d4e8dc385d9258220c31 Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Dmitry Antipov dmantipov@yandex.ru Tested-by: Oleksij Rempel o.rempel@pengutronix.de Acked-by: Oleksij Rempel o.rempel@pengutronix.de Link: https://patch.msgid.link/20241105094823.2403806-1-dmantipov@yandex.ru [mkl: clean up commit message] Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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 1d926a0372e61..7cef19287a3ff 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -1489,7 +1489,7 @@ 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));