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authorEric Dumazet <edumazet@google.com>2023-03-16 04:10:06 +0300
committerDavid S. Miller <davem@davemloft.net>2023-03-17 11:52:05 +0300
commitb9d83ab8a708f23a4001d60e9d8d0b3be3d9f607 (patch)
tree23a6ab230684c1a42dd59e0e146c5f035b6eade0 /net/packet
parentdc021e6c24e1edd809e4f109783c48e8a74b2d8c (diff)
downloadlinux-b9d83ab8a708f23a4001d60e9d8d0b3be3d9f607.tar.xz
net/packet: annotate accesses to po->xmit
po->xmit can be set from setsockopt(PACKET_QDISC_BYPASS), while read locklessly. Use READ_ONCE()/WRITE_ONCE() to avoid potential load/store tearing issues. Fixes: d346a3fae3ff ("packet: introduce PACKET_QDISC_BYPASS socket option") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d4e76e2ae153..d25dd9f63cc4 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -307,7 +307,8 @@ static void packet_cached_dev_reset(struct packet_sock *po)
static bool packet_use_direct_xmit(const struct packet_sock *po)
{
- return po->xmit == packet_direct_xmit;
+ /* Paired with WRITE_ONCE() in packet_setsockopt() */
+ return READ_ONCE(po->xmit) == packet_direct_xmit;
}
static u16 packet_pick_tx_queue(struct sk_buff *skb)
@@ -2867,7 +2868,8 @@ tpacket_error:
packet_inc_pending(&po->tx_ring);
status = TP_STATUS_SEND_REQUEST;
- err = po->xmit(skb);
+ /* Paired with WRITE_ONCE() in packet_setsockopt() */
+ err = READ_ONCE(po->xmit)(skb);
if (unlikely(err != 0)) {
if (err > 0)
err = net_xmit_errno(err);
@@ -3070,7 +3072,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
virtio_net_hdr_set_proto(skb, &vnet_hdr);
}
- err = po->xmit(skb);
+ /* Paired with WRITE_ONCE() in packet_setsockopt() */
+ err = READ_ONCE(po->xmit)(skb);
if (unlikely(err != 0)) {
if (err > 0)
err = net_xmit_errno(err);
@@ -4007,7 +4010,8 @@ packet_setsockopt(struct socket *sock, int level, int optname, sockptr_t optval,
if (copy_from_sockptr(&val, optval, sizeof(val)))
return -EFAULT;
- po->xmit = val ? packet_direct_xmit : dev_queue_xmit;
+ /* Paired with all lockless reads of po->xmit */
+ WRITE_ONCE(po->xmit, val ? packet_direct_xmit : dev_queue_xmit);
return 0;
}
default: