From b635e4b808bf45ebd66e9f687e18b9af6bd634c1 Mon Sep 17 00:00:00 2001 From: Michael Pratt Date: Tue, 1 Dec 2020 17:24:33 -0500 Subject: [PATCH] time, runtime: don't set timer when = 0 timer when == 0, in the context of timer0When and timerModifiedEarliest, is a sentinel value meaning there are no timers on the heap. TestCheckRuntimeTimerOverflow reaching into the runtime to set a timer to when = 0 when it is otherwise not possible breaks this invariant. After golang.org/cl/258303, we will no longer detect and run this timer, thus blocking any other timers lower on the heap from running. This manifests as random timers failing to fire in other tests. The need to set this overflowed timer to when = 0 is gone with the old timer proc implementation, so we can simply remove it. Fixes #42424 Change-Id: Iea32100136ad8ec1bedfa77b1e7d9ed868812838 Reviewed-on: https://go-review.googlesource.com/c/go/+/274632 Reviewed-by: Ian Lance Taylor Run-TryBot: Michael Pratt TryBot-Result: Go Bot Trust: Michael Pratt --- src/runtime/time.go | 2 ++ src/time/internal_test.go | 10 ---------- 2 files changed, 2 insertions(+), 10 deletions(-) diff --git a/src/runtime/time.go b/src/runtime/time.go index 75b66f8492..83d93c5686 100644 --- a/src/runtime/time.go +++ b/src/runtime/time.go @@ -23,6 +23,8 @@ type timer struct { // Timer wakes up at when, and then at when+period, ... (period > 0 only) // each time calling f(arg, now) in the timer goroutine, so f must be // a well-behaved function and not block. + // + // when must be positive on an active timer. when int64 period int64 f func(interface{}, uintptr) diff --git a/src/time/internal_test.go b/src/time/internal_test.go index 35ce69b228..e70b6f34de 100644 --- a/src/time/internal_test.go +++ b/src/time/internal_test.go @@ -53,18 +53,8 @@ func CheckRuntimeTimerOverflow() { t := NewTimer(1) defer func() { - // Subsequent tests won't work correctly if we don't stop the - // overflow timer and kick the timer proc back into service. - // - // The timer proc is now sleeping and can only be awoken by - // adding a timer to the *beginning* of the heap. We can't - // wake it up by calling NewTimer since other tests may have - // left timers running that should have expired before ours. - // Instead we zero the overflow timer duration and start it - // once more. stopTimer(r) t.Stop() - resetTimer(r, 0) }() // If the test fails, we will hang here until the timeout in the -- 2.48.1