From: Eric Dumazet edumazet@google.com
[ Upstream commit d1b5bee4c8be01585033be9b3a8878789285285f ]
There is a known race in packet_sendmsg(), addressed in commit 32d3182cd2cd ("net/packet: fix race in tpacket_snd()")
Now we have data_race(), we can use it to avoid a future KCSAN warning, as syzbot loves stressing af_packet sockets :)
Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/packet/af_packet.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index c52557ec7fb3..84d8921391c3 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3034,10 +3034,13 @@ static int packet_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) struct sock *sk = sock->sk; struct packet_sock *po = pkt_sk(sk);
- if (po->tx_ring.pg_vec) + /* Reading tx_ring.pg_vec without holding pg_vec_lock is racy. + * tpacket_snd() will redo the check safely. + */ + if (data_race(po->tx_ring.pg_vec)) return tpacket_snd(po, msg); - else - return packet_snd(sock, msg, len); + + return packet_snd(sock, msg, len); }
/*