| Message ID | 20200826120113.3244-1-zhudi21@huawei.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | netlink: fix a data race in netlink_rcv_wake() | expand |
From: zhudi <zhudi21@huawei.com> Date: Wed, 26 Aug 2020 20:01:13 +0800 > The data races were reported by KCSAN: > BUG: KCSAN: data-race in netlink_recvmsg / skb_queue_tail ... > Since the write is under sk_receive_queue->lock but the read > is done as lockless. so fix it by using skb_queue_empty_lockless() > instead of skb_queue_empty() for the read in netlink_rcv_wake() > > Signed-off-by: zhudi <zhudi21@huawei.com> Applied, thank you.
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index b5f30d7d30d0..d2d1448274f5 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -353,7 +353,7 @@ static void netlink_rcv_wake(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); - if (skb_queue_empty(&sk->sk_receive_queue)) + if (skb_queue_empty_lockless(&sk->sk_receive_queue)) clear_bit(NETLINK_S_CONGESTED, &nlk->state); if (!test_bit(NETLINK_S_CONGESTED, &nlk->state)) wake_up_interruptible(&nlk->wait);
The data races were reported by KCSAN: BUG: KCSAN: data-race in netlink_recvmsg / skb_queue_tail write (marked) to 0xffff8c0986e5a8c8 of 8 bytes by interrupt on cpu 3: skb_queue_tail+0xcc/0x120 __netlink_sendskb+0x55/0x80 netlink_broadcast_filtered+0x465/0x7e0 nlmsg_notify+0x8f/0x120 rtnl_notify+0x8e/0xb0 __neigh_notify+0xf2/0x120 neigh_update+0x927/0xde0 arp_process+0x8a3/0xf50 arp_rcv+0x27c/0x3b0 __netif_receive_skb_core+0x181c/0x1840 __netif_receive_skb+0x38/0xf0 netif_receive_skb_internal+0x77/0x1c0 napi_gro_receive+0x1bd/0x1f0 e1000_clean_rx_irq+0x538/0xb20 [e1000] e1000_clean+0x5e4/0x1340 [e1000] net_rx_action+0x310/0x9d0 __do_softirq+0xe8/0x308 irq_exit+0x109/0x110 do_IRQ+0x7f/0xe0 ret_from_intr+0x0/0x1d 0xffffffffffffffff read to 0xffff8c0986e5a8c8 of 8 bytes by task 1463 on cpu 0: netlink_recvmsg+0x40b/0x820 sock_recvmsg+0xc9/0xd0 ___sys_recvmsg+0x1a4/0x3b0 __sys_recvmsg+0x86/0x120 __x64_sys_recvmsg+0x52/0x70 do_syscall_64+0xb5/0x360 entry_SYSCALL_64_after_hwframe+0x65/0xca 0xffffffffffffffff Since the write is under sk_receive_queue->lock but the read is done as lockless. so fix it by using skb_queue_empty_lockless() instead of skb_queue_empty() for the read in netlink_rcv_wake() Signed-off-by: zhudi <zhudi21@huawei.com> --- net/netlink/af_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)