Date: Tue, 28 Jul 2026 20:24:04 +0000 From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 52b7cbcb78c1 - main - tcp: improve handling of stopped timers Message-ID: <6a690fe4.474cd.3f45cf@gitrepo.freebsd.org>
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The branch main has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=52b7cbcb78c14e89f6faec8da5acc2caa3d37208 commit 52b7cbcb78c14e89f6faec8da5acc2caa3d37208 Author: Michael Tuexen <tuexen@FreeBSD.org> AuthorDate: 2026-07-28 20:15:22 +0000 Commit: Michael Tuexen <tuexen@FreeBSD.org> CommitDate: 2026-07-28 20:15:22 +0000 tcp: improve handling of stopped timers When a TCP timer is stopped, t_timers[] is set to SBT_MAX. Adding the corresponding t_precisions[], if it is not zero, would result in overflows in tcp_timer_next(). To avoid this, skip stopped timers. The problem was identified while debugging uperf by Lukas Book and an initial patch was provided by him. The committed patch was suggested by glebius. The problem can be observed by running netstat -nxptcp and looking for negative timer values and by observing very long running timers in some cases. Reported by: Lukas Book <lkbook@outlook.de> Reviewed by: glebius Differential Revision: https://reviews.freebsd.org/D58484 --- sys/netinet/tcp_timer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sys/netinet/tcp_timer.c b/sys/netinet/tcp_timer.c index ca242f2be627..57a4f3080df0 100644 --- a/sys/netinet/tcp_timer.c +++ b/sys/netinet/tcp_timer.c @@ -858,6 +858,8 @@ tcp_timer_next(struct tcpcb *tp, sbintime_t *precision) sbintime_t after, before; for (i = 0, rv = TT_N, after = before = SBT_MAX; i < TT_N; i++) { + if (tp->t_timers[i] == SBT_MAX) + continue; if (tp->t_timers[i] < after) { after = tp->t_timers[i]; rv = i;home | help
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