diff options
| author | Altan Hacigumus <ahacigu.linux@gmail.com> | 2026-04-24 04:46:38 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-28 05:16:07 +0300 |
| commit | 2b9f6f7065d4cfb65ba19126e0b35ac4544c3f3a (patch) | |
| tree | cbdd30643e24bbbea490bb652cffa18874c0344e | |
| parent | cc427d24ac6442ffdeafd157a63c7c5b73ed4de4 (diff) | |
| download | linux-2b9f6f7065d4cfb65ba19126e0b35ac4544c3f3a.tar.xz | |
tcp: make probe0 timer handle expired user timeout
tcp_clamp_probe0_to_user_timeout() computes remaining time in jiffies
using subtraction with an unsigned lvalue. If elapsed probing time
exceeds the configured TCP_USER_TIMEOUT, the underflow yields a large
value.
This ends up re-arming the probe timer for a full backoff interval
instead of expiring immediately, delaying connection teardown beyond
the configured timeout.
Fix this by preventing underflow so user-set timeout expiration is
handled correctly without extending the probe timer.
Fixes: 344db93ae3ee ("tcp: make TCP_USER_TIMEOUT accurate for zero window probes")
Link: https://lore.kernel.org/r/20260414013634.43997-1-ahacigu.linux@gmail.com
Signed-off-by: Altan Hacigumus <ahacigu.linux@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260424014639.54110-1-ahacigu.linux@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/tcp_timer.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 8d791a954cd6..322db13333c7 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -50,7 +50,8 @@ static u32 tcp_clamp_rto_to_user_timeout(const struct sock *sk) u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when) { const struct inet_connection_sock *icsk = inet_csk(sk); - u32 remaining, user_timeout; + u32 user_timeout; + s32 remaining; s32 elapsed; user_timeout = READ_ONCE(icsk->icsk_user_timeout); @@ -61,7 +62,7 @@ u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when) if (unlikely(elapsed < 0)) elapsed = 0; remaining = msecs_to_jiffies(user_timeout) - elapsed; - remaining = max_t(u32, remaining, TCP_TIMEOUT_MIN); + remaining = max_t(int, remaining, TCP_TIMEOUT_MIN); return min_t(u32, remaining, when); } |