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go/test/fixedbugs/issue25897b.go
Keith Randall 38c129b4f0 runtime: get map of args of unstarted goroutines like we do for defers
Normally, reflect.makeFuncStub records the context value at a known
point in the stack frame, so that the runtime can get the argument map
for reflect.makeFuncStub from that known location.

This doesn't work for defers or goroutines that haven't started yet,
because they haven't allocated a frame or run an instruction yet. The
argument map must be extracted from the context value. We already do
this for defers (the non-nil ctxt arg to getArgInfo), we just need to
do it for unstarted goroutines as well.

When we traceback a goroutine, remember the context value from
g.sched.  Use it for the first frame we find.

(We never need it for deeper frames, because we normally don't stop at
 the start of reflect.makeFuncStub, as it is nosplit. With this CL we
 could allow makeFuncStub to no longer be nosplit.)

Fixes #25897

Change-Id: I427abf332a741a80728cdc0b8412aa8f37e7c418
Reviewed-on: https://go-review.googlesource.com/c/go/+/180258
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-06-03 18:50:30 +00:00

39 lines
651 B
Go

// run
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Make sure the runtime can scan args of an unstarted goroutine
// which starts with a reflect-generated function.
package main
import (
"reflect"
"runtime"
)
const N = 100
type T struct {
}
func (t *T) Foo(c chan bool) {
c <- true
}
func main() {
t := &T{}
runtime.GOMAXPROCS(1)
c := make(chan bool, N)
for i := 0; i < N; i++ {
f := reflect.ValueOf(t).MethodByName("Foo").Interface().(func(chan bool))
go f(c)
}
runtime.GC()
for i := 0; i < N; i++ {
<-c
}
}