runtime: race condition raised with parallel tests, panic(nil) and -race #64649
Description
Go version
go version go1.21.5 darwin/arm64
What operating system and processor architecture are you using (go env)?
- Local (Apple M2)
- GitHub Actions (x86)What did you do?
I have a testsuite for my github.com/dolmen-go/rendezvous package.
$ git clone https://github.com/dolmen-go/rendezvous.git
$ cd rendezvous
$ git checkout 44e68d01a216b3755c9ba5dc75835074c3e5e866
$ go version
go version go1.21.5 darwin/arm64
$ go test -v -race -run 'Test(One|Two)' "-gcflags=all=-trimpath=$(go env GOPATH)" github.com/dolmen-go/rendezvous
=== RUN TestOne
=== PAUSE TestOne
=== RUN TestTwo
=== PAUSE TestTwo
=== CONT TestOne
=== CONT TestTwo
==================
WARNING: DATA RACE
Read at 0x00c000076560 by goroutine 14:
internal/godebug.(*Setting).IncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/internal/godebug/godebug.go:102 +0x58
internal/godebug.(*Setting).IncNonDefault-fm()
<autogenerated>:1 +0x34
runtime.(*godebugInc).IncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/runtime/runtime.go:111 +0xd0
github.com/dolmen-go/rendezvous.WaitAll.func1()
src/github.com/dolmen-go/rendezvous/rendezvous.go:56 +0xec
github.com/dolmen-go/rendezvous.WaitAll.func2()
src/github.com/dolmen-go/rendezvous/rendezvous.go:57 +0x44
Previous write at 0x00c000076560 by goroutine 12:
internal/godebug.New()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/internal/godebug/godebug.go:74 +0x40
internal/godebug.newIncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/internal/godebug/godebug.go:203 +0x28
runtime.(*godebugInc).IncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/runtime/runtime.go:108 +0x84
github.com/dolmen-go/rendezvous.WaitAll.func1()
src/github.com/dolmen-go/rendezvous/rendezvous.go:56 +0xec
github.com/dolmen-go/rendezvous.WaitAll.func2()
src/github.com/dolmen-go/rendezvous/rendezvous.go:57 +0x44
Goroutine 14 (running) created at:
github.com/dolmen-go/rendezvous.WaitAll()
src/github.com/dolmen-go/rendezvous/rendezvous.go:47 +0x210
github.com/dolmen-go/rendezvous_test.TestTwo()
src/github.com/dolmen-go/rendezvous/rendezvous_test.go:118 +0xe4
testing.tRunner()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/testing/testing.go:1595 +0x1b0
testing.(*T).Run.func1()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/testing/testing.go:1648 +0x40
Goroutine 12 (running) created at:
github.com/dolmen-go/rendezvous.WaitAll()
src/github.com/dolmen-go/rendezvous/rendezvous.go:47 +0x210
github.com/dolmen-go/rendezvous_test.TestOne()
src/github.com/dolmen-go/rendezvous/rendezvous_test.go:104 +0x180
testing.tRunner()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/testing/testing.go:1595 +0x1b0
testing.(*T).Run.func1()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/testing/testing.go:1648 +0x40
==================
=== NAME TestOne
testing.go:1465: race detected during execution of test
--- FAIL: TestOne (0.00s)
=== NAME TestTwo
testing.go:1465: race detected during execution of test
--- FAIL: TestTwo (0.00s)
FAIL
exit status 1
FAIL github.com/dolmen-go/rendezvous 0.104s
Some characteristics that might be relevant:
- The
rendezvouspackage launches goroutines in its tests. - The
rendezvoustestsuite uses parallel testing at top testing level:
func TestOne(t *testing.T) {
t.Parallel()
// ...
}
func TestTwo(t *testing.T) {
t.Parallel()
// ...
}This issue is also visible on GitHub Actions: https://github.com/dolmen-go/rendezvous/actions/runs/7147035848/job/19465833264#step:4:32
What did you expect to see?
Test success like with previous Go versions.
What did you see instead?
Race condition in runtime:
WARNING: DATA RACE
Read at 0x00c000076560 by goroutine 14:
internal/godebug.(*Setting).IncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/internal/godebug/godebug.go:102 +0x58
internal/godebug.(*Setting).IncNonDefault-fm()
<autogenerated>:1 +0x34
runtime.(*godebugInc).IncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/runtime/runtime.go:111 +0xd0
github.com/dolmen-go/rendezvous.WaitAll.func1()
src/github.com/dolmen-go/rendezvous/rendezvous.go:56 +0xec
github.com/dolmen-go/rendezvous.WaitAll.func2()
src/github.com/dolmen-go/rendezvous/rendezvous.go:57 +0x44
Previous write at 0x00c000076560 by goroutine 12:
internal/godebug.New()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/internal/godebug/godebug.go:74 +0x40
internal/godebug.newIncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/internal/godebug/godebug.go:203 +0x28
runtime.(*godebugInc).IncNonDefault()
/opt/homebrew/Cellar/go/1.21.5/libexec/src/runtime/runtime.go:108 +0x84
github.com/dolmen-go/rendezvous.WaitAll.func1()
src/github.com/dolmen-go/rendezvous/rendezvous.go:56 +0xec
github.com/dolmen-go/rendezvous.WaitAll.func2()
src/github.com/dolmen-go/rendezvous/rendezvous.go:57 +0x44
Link to runtime source: https://github.com/golang/go/blob/go1.21.5/src/runtime/runtime.go#L97
A comment says:
// If other goroutines are racing here, no big deal. One will win,
// and all the inc functions will be using the same underlying
// *godebug.Setting.If this is related, I think this is "big deal" as running go test -race in CI is quite common. (Calling t.Parallel() from top level tests is not so common, this is unfortunate, and this issue blocks from pushing for it)