diff options
Diffstat (limited to 'src/runtime/time.go')
| -rw-r--r-- | src/runtime/time.go | 39 |
1 files changed, 33 insertions, 6 deletions
diff --git a/src/runtime/time.go b/src/runtime/time.go index 75b66f8492..8ab2a03430 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) @@ -185,6 +187,9 @@ func timeSleep(ns int64) { t.f = goroutineReady t.arg = gp t.nextwhen = nanotime() + ns + if t.nextwhen < 0 { // check for overflow. + t.nextwhen = maxWhen + } gopark(resetForSleep, unsafe.Pointer(t), waitReasonSleep, traceEvGoSleep, 1) } @@ -242,10 +247,14 @@ func goroutineReady(arg interface{}, seq uintptr) { // That avoids the risk of changing the when field of a timer in some P's heap, // which could cause the heap to become unsorted. func addtimer(t *timer) { - // when must never be negative; otherwise runtimer will overflow - // during its delta calculation and never expire other runtime timers. - if t.when < 0 { - t.when = maxWhen + // when must be positive. A negative value will cause runtimer to + // overflow during its delta calculation and never expire other runtime + // timers. Zero will cause checkTimers to fail to notice the timer. + if t.when <= 0 { + throw("timer when must be positive") + } + if t.period < 0 { + throw("timer period must be non-negative") } if t.status != timerNoStatus { throw("addtimer called with initialized timer") @@ -406,8 +415,11 @@ func dodeltimer0(pp *p) { // This is called by the netpoll code or time.Ticker.Reset or time.Timer.Reset. // Reports whether the timer was modified before it was run. func modtimer(t *timer, when, period int64, f func(interface{}, uintptr), arg interface{}, seq uintptr) bool { - if when < 0 { - when = maxWhen + if when <= 0 { + throw("timer when must be positive") + } + if period < 0 { + throw("timer period must be non-negative") } status := uint32(timerNoStatus) @@ -597,8 +609,14 @@ func moveTimers(pp *p, timers []*timer) { for { switch s := atomic.Load(&t.status); s { case timerWaiting: + if !atomic.Cas(&t.status, s, timerMoving) { + continue + } t.pp = 0 doaddtimer(pp, t) + if !atomic.Cas(&t.status, timerMoving, timerWaiting) { + badTimer() + } break loop case timerModifiedEarlier, timerModifiedLater: if !atomic.Cas(&t.status, s, timerMoving) { @@ -846,6 +864,9 @@ func runOneTimer(pp *p, t *timer, now int64) { // Leave in heap but adjust next time to fire. delta := t.when - now t.when += t.period * (1 + -delta/t.period) + if t.when < 0 { // check for overflow. + t.when = maxWhen + } siftdownTimer(pp.timers, 0) if !atomic.Cas(&t.status, timerRunning, timerWaiting) { badTimer() @@ -1064,6 +1085,9 @@ func siftupTimer(t []*timer, i int) { badTimer() } when := t[i].when + if when <= 0 { + badTimer() + } tmp := t[i] for i > 0 { p := (i - 1) / 4 // parent @@ -1084,6 +1108,9 @@ func siftdownTimer(t []*timer, i int) { badTimer() } when := t[i].when + if when <= 0 { + badTimer() + } tmp := t[i] for { c := i*4 + 1 // left child |