Hi! > From: Greg Kroah-Hartman <[email protected]> > > From: Eric Dumazet <[email protected]>
Dup.
> We need to add READ_ONCE() annotations, and also make
> sure write sides use corresponding WRITE_ONCE() to avoid
> store-tearing.
> @@ -1037,7 +1037,7 @@ new_segment:
> sk->sk_wmem_queued += copy;
> sk_mem_charge(sk, copy);
> skb->ip_summed = CHECKSUM_PARTIAL;
> - tp->write_seq += copy;
> + WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
> TCP_SKB_CB(skb)->end_seq += copy;
> tcp_skb_pcount_set(skb, 0);
>
I wonder if this needs to do READ_ONCE, too?
> @@ -1391,7 +1391,7 @@ new_segment:
> if (!copied)
> TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
>
> - tp->write_seq += copy;
> + WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
> TCP_SKB_CB(skb)->end_seq += copy;
> tcp_skb_pcount_set(skb, 0);
>
And here.
> @@ -2593,9 +2594,12 @@ int tcp_disconnect(struct sock *sk, int
> sock_reset_flag(sk, SOCK_DONE);
> tp->srtt_us = 0;
> tp->rcv_rtt_last_tsecr = 0;
> - tp->write_seq += tp->max_window + 2;
> - if (tp->write_seq == 0)
> - tp->write_seq = 1;
> +
> + seq = tp->write_seq + tp->max_window + 2;
> + if (!seq)
> + seq = 1;
> + WRITE_ONCE(tp->write_seq, seq);
And here.
> --- a/net/ipv4/tcp_minisocks.c
> +++ b/net/ipv4/tcp_minisocks.c
> @@ -510,7 +510,7 @@ struct sock *tcp_create_openreq_child(co
> newtp->app_limited = ~0U;
>
> tcp_init_xmit_timers(newsk);
> - newtp->write_seq = newtp->pushed_seq = treq->snt_isn + 1;
> + WRITE_ONCE(newtp->write_seq, newtp->pushed_seq = treq->snt_isn + 1);
Would it be better to do assignment to pushed_seq outside of
WRITE_ONCE macro? This is ... "interesting".
Best regards,
Pavel
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