Go version
go version go1.25.2 X:nodwarf5 linux/amd64
Output of go env in your module/workspace:
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/home/username/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/username/.config/go/env'
GOEXE=''
GOEXPERIMENT='nodwarf5'
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3427196454=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/dev/null'
GOMODCACHE='/home/username/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/username/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/lib/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/username/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.25.2 X:nodwarf5'
GOWORK=''
PKG_CONFIG='pkg-config'
What did you do?
Hello! Here is a minimal test:
package main
import (
"runtime"
"testing"
"testing/synctest"
)
func Test(t *testing.T) {
synctest.Test(t, func(t *testing.T) {
done := false
go func() { // the line below causes problem. Works only with rate > 1
runtime.SetBlockProfileRate(2)
done = true
}()
synctest.Wait()
if !done {
t.Fatal("somehow not done")
}
})
}What did you see happen?
Test is flaky, needs to be run many times.
go test -v -count 1000 -failfast ./
=== RUN Test
main_test.go:18: somehow not done
--- FAIL: Test (0.00s)
panic: deadlock: main bubble goroutine has exited but blocked goroutines remain [recovered, repanicked]
goroutine 21 [running]:
testing.tRunner.func1.2({0x566980, 0xc0000ca0f0})
/usr/lib/go/src/testing/testing.go:1872 +0x237
testing.tRunner.func1()
/usr/lib/go/src/testing/testing.go:1875 +0x35b
panic({0x566980?, 0xc0000ca0f0?})
/usr/lib/go/src/runtime/panic.go:783 +0x132
internal/synctest.Run(0xc0000aa160)
/usr/lib/go/src/runtime/synctest.go:251 +0x2de
testing/synctest.Test(0xc000092c40, 0x58d2b8)
/usr/lib/go/src/testing/synctest/synctest.go:282 +0x90
blockratetest.Test(0xc000092c40?)
/home/blockratetest/main_test.go:10 +0x1a
testing.tRunner(0xc000092c40, 0x58d1d8)
/usr/lib/go/src/testing/testing.go:1934 +0xea
created by testing.(*T).Run in goroutine 1
/usr/lib/go/src/testing/testing.go:1997 +0x465
goroutine 24 [sleep (durable), synctest bubble 1]:
time.Sleep(0xf4240)
/usr/lib/go/src/runtime/time.go:361 +0x145
runtime.SetBlockProfileRate(0x2)
/usr/lib/go/src/runtime/mprof.go:497 +0x2c
blockratetest.Test.func1.1()
/home/blockratetest/main_test.go:13 +0x25
created by blockratetest.Test.func1 in goroutine 23
/home/blockratetest/main_test.go:12 +0x66
FAIL blockratetest 0.005s
FAIL
What did you expect to see?
Test is almost copy of the example from https://pkg.go.dev/testing/synctest#hdr-Blocking .
It is not clear why calling runtime.SetBlockProfileRate causes test to fail - documentation of runtime/synctest package doesn't mention this behavior or it is not clear.
Go version
go version go1.25.2 X:nodwarf5 linux/amd64
Output of
go envin your module/workspace:What did you do?
Hello! Here is a minimal test:
What did you see happen?
Test is flaky, needs to be run many times.
What did you expect to see?
Test is almost copy of the example from https://pkg.go.dev/testing/synctest#hdr-Blocking .
It is not clear why calling
runtime.SetBlockProfileRatecauses test to fail - documentation of runtime/synctest package doesn't mention this behavior or it is not clear.