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authorEric Dumazet <edumazet@google.com>2021-06-10 09:00:12 -0700
committerDavid S. Miller <davem@davemloft.net>2021-06-10 14:12:54 -0700
commitd1b5bee4c8be01585033be9b3a8878789285285f (patch)
treeab9212ee4357ee19d60508de497524d1ec18b485
parentb71eaed8c04f72a919a9c44e83e4ee254e69e7f3 (diff)
downloadlinux-d1b5bee4c8be01585033be9b3a8878789285285f.tar.bz2
net/packet: annotate data race in packet_sendmsg()
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>
-rw-r--r--net/packet/af_packet.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ae906eb4b269..74e6e45a8e84 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);
}
/*