Commit d1b5bee4 authored Jun 10, 2021 by Eric Dumazet Committed by David S. Miller Jun 10, 2021

net/packet: annotate data race in packet_sendmsg()



There is a known race in packet_sendmsg(), addressed
in commit 32d3182c ("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>

parent b71eaed8

net/packet/af_packet.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -3034,9 +3034,12 @@ 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);
		}