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| author | Eric Dumazet <edumazet@google.com> | 2024-06-07 12:56:52 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-06-10 19:50:10 -0700 |
| commit | 36534d3c54537bf098224a32dc31397793d4594d (patch) | |
| tree | 74e1e08dbe4c54a9d2841bf054b86aa09d2010d9 /net/ipv4 | |
| parent | 70b3c88cec7eed6080c8c37f0d2cc4bc46c08852 (diff) | |
| download | linux-stable-36534d3c54537bf098224a32dc31397793d4594d.tar.gz linux-stable-36534d3c54537bf098224a32dc31397793d4594d.tar.bz2 linux-stable-36534d3c54537bf098224a32dc31397793d4594d.zip | |
tcp: use signed arithmetic in tcp_rtx_probe0_timed_out()
Due to timer wheel implementation, a timer will usually fire
after its schedule.
For instance, for HZ=1000, a timeout between 512ms and 4s
has a granularity of 64ms.
For this range of values, the extra delay could be up to 63ms.
For TCP, this means that tp->rcv_tstamp may be after
inet_csk(sk)->icsk_timeout whenever the timer interrupt
finally triggers, if one packet came during the extra delay.
We need to make sure tcp_rtx_probe0_timed_out() handles this case.
Fixes: e89688e3e978 ("net: tcp: fix unexcepted socket die when snd_wnd is 0")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Menglong Dong <imagedong@tencent.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://lore.kernel.org/r/20240607125652.1472540-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 83fe7f62f7f1..5bfd76a31af6 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -485,8 +485,12 @@ static bool tcp_rtx_probe0_timed_out(const struct sock *sk, { const struct tcp_sock *tp = tcp_sk(sk); const int timeout = TCP_RTO_MAX * 2; - u32 rcv_delta; + s32 rcv_delta; + /* Note: timer interrupt might have been delayed by at least one jiffy, + * and tp->rcv_tstamp might very well have been written recently. + * rcv_delta can thus be negative. + */ rcv_delta = inet_csk(sk)->icsk_timeout - tp->rcv_tstamp; if (rcv_delta <= timeout) return false; |