iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tcp: annotate tp->copied_seq lockless reads

Browse Source 
There are few places where we fetch tp->copied_seq while
this field can change from IRQ or other cpu.

We need to add READ_ONCE() annotations, and also make
sure write sides use corresponding WRITE_ONCE() to avoid
store-tearing.

Note that tcp_inq_hint() was already using READ_ONCE(tp->copied_seq)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2019-10-10 20:17:40 -07:00
committed by David S. Miller
parent dba7d9b8c7
commit 7db48e9839
7 changed files with 19 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
net/ipv4/tcp_input.c
View File

@ -5961,7 +5961,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
/* Remember, tcp_poll() does not lock socket!
* Change state from SYN-SENT only after copied_seq
* is initialized. */
tp->copied_seq = tp->rcv_nxt;
WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
smc_check_reset_syn(tp);
@ -6036,7 +6036,7 @@ discard:
}
WRITE_ONCE(tp->rcv_nxt, TCP_SKB_CB(skb)->seq + 1);
tp->copied_seq = tp->rcv_nxt;
WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
/* RFC1323: The window in SYN & SYN/ACK segments is
@ -6216,7 +6216,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
tcp_try_undo_spurious_syn(sk);
tp->retrans_stamp = 0;
tcp_init_transfer(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
tp->copied_seq = tp->rcv_nxt;
WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
}
smp_mb();
tcp_set_state(sk, TCP_ESTABLISHED);