testing: data race between parallel panicking and normal subtest

What version of Go are you using (`go version`)?

$ go version
go version go1.14 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (`go env`)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/changkun/Library/Caches/go-build"
GOENV="/Users/changkun/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/changkun/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/Cellar/go/1.14/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.14/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/j_/h4j7spgj3znbfxcbbph5fp4w0000gn/T/go-build613651133=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

package main_test

import "testing"

func TestA(t *testing.T) {
	t.Run("1", func(t *testing.T) {
		t.Run("1", func(t *testing.T) {
			t.Parallel()
			panic("A1/1 panics")
		})
		t.Run("2", func(t *testing.T) {
			t.Parallel()
			println("A/1/2 is ok")
		})
	})
}

$ go test -v -race -count=1 .

What did you expect to see?

=== RUN   TestA
=== RUN   TestA/1
=== RUN   TestA/1/1
=== PAUSE TestA/1/1
=== RUN   TestA/1/2
=== PAUSE TestA/1/2
=== CONT  TestA/1/1
=== CONT  TestA/1/2
A/1/2 is ok
--- FAIL: TestA (0.00s)
    --- FAIL: TestA/1 (0.00s)
        --- PASS: TestA/1/2 (0.00s)
        --- FAIL: TestA/1/1 (0.00s)
panic: A1/1 panics [recovered]
        panic: A1/1 panics

goroutine 20 [running]:
testing.tRunner.func1.1(0x1110560, 0x1168870)
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:941 +0x3d0
testing.tRunner.func1(0xc0000cc360)
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:944 +0x3f9
panic(0x1110560, 0x1168870)
        /usr/local/Cellar/go/1.14/libexec/src/runtime/panic.go:967 +0x15d
_/Users/changkun/Desktop/testing/parallel_test.TestA.func1.1(0xc0000cc360)
        /Users/changkun/Desktop/testing/parallel/main_test.go:13 +0x47
testing.tRunner(0xc0000cc360, 0x114a410)
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0xdc
created by testing.(*T).Run
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1043 +0x357
FAIL    _/Users/changkun/Desktop/testing/parallel       0.144s
FAIL

What did you see instead?

Data race appears in Go 1.14 and not in Go 1.13.8:

=== RUN   TestA
=== RUN   TestA/1
=== RUN   TestA/1/1
=== PAUSE TestA/1/1
=== RUN   TestA/1/2
=== PAUSE TestA/1/2
=== CONT  TestA/1/2
A/1/2 is ok
=== CONT  TestA/1/1
==================
WARNING: DATA RACE
Read at 0x00c000156258 by goroutine 9:
  testing.indenter.Write()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:533 +0xd9
  fmt.Fprintf()
      /usr/local/Cellar/go/1.14/libexec/src/fmt/print.go:205 +0xcc
  testing.tRunner.func1.1()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:934 +0x3a8
  testing.tRunner.func1()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:944 +0x5ff
  runtime.call32()
      /usr/local/Cellar/go/1.14/libexec/src/runtime/asm_amd64.s:539 +0x3a
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1eb

Previous write at 0x00c000156258 by goroutine 10:
  testing.indenter.Write()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:533 +0x17b
  fmt.Fprintf()
      /usr/local/Cellar/go/1.14/libexec/src/fmt/print.go:205 +0xcc
  testing.(*common).flushToParent()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:509 +0x137
  testing.(*T).report()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1227 +0x3b6
  testing.tRunner.func1()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:974 +0x452
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:996 +0x20d

Goroutine 9 (running) created at:
  testing.(*T).Run()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1043 +0x660
  _/Users/changkun/Desktop/testing/parallel_test.TestA.func1()
      /Users/changkun/Desktop/testing/parallel/main_test.go:11 +0x5d
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1eb

Goroutine 10 (running) created at:
  testing.(*T).Run()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1043 +0x660
  _/Users/changkun/Desktop/testing/parallel_test.TestA.func1()
      /Users/changkun/Desktop/testing/parallel/main_test.go:15 +0x8c
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1eb
==================
==================
WARNING: DATA RACE
Read at 0x00c00015c040 by goroutine 9:
  runtime.growslice()
      /usr/local/Cellar/go/1.14/libexec/src/runtime/slice.go:76 +0x0
  testing.indenter.Write()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:533 +0x341
  fmt.Fprintf()
      /usr/local/Cellar/go/1.14/libexec/src/fmt/print.go:205 +0xcc
  testing.tRunner.func1.1()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:934 +0x3a8
  testing.tRunner.func1()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:944 +0x5ff
  runtime.call32()
      /usr/local/Cellar/go/1.14/libexec/src/runtime/asm_amd64.s:539 +0x3a
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1eb

Previous write at 0x00c00015c044 by goroutine 10:
  runtime.slicecopy()
      /usr/local/Cellar/go/1.14/libexec/src/runtime/slice.go:197 +0x0
  testing.indenter.Write()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:534 +0x252
  fmt.Fprintf()
      /usr/local/Cellar/go/1.14/libexec/src/fmt/print.go:205 +0xcc
  testing.(*common).flushToParent()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:509 +0x137
  testing.(*T).report()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1227 +0x3b6
  testing.tRunner.func1()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:974 +0x452
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:996 +0x20d

Goroutine 9 (running) created at:
  testing.(*T).Run()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1043 +0x660
  _/Users/changkun/Desktop/testing/parallel_test.TestA.func1()
      /Users/changkun/Desktop/testing/parallel/main_test.go:11 +0x5d
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1eb

Goroutine 10 (running) created at:
  testing.(*T).Run()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1043 +0x660
  _/Users/changkun/Desktop/testing/parallel_test.TestA.func1()
      /Users/changkun/Desktop/testing/parallel/main_test.go:15 +0x8c
  testing.tRunner()
      /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1eb
==================
--- FAIL: TestA (0.00s)
    --- FAIL: TestA/1 (0.00s)
        --- PASS: TestA/1/2 (0.00s)
        --- FAIL: TestA/1/1 (0.00s)
panic: A1/1 panics [recovered]
        panic: A1/1 panics

goroutine 21 [running]:
testing.tRunner.func1.1(0x11d6b60, 0x123d440)
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:941 +0x5d0
testing.tRunner.func1(0xc000156360)
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:944 +0x600
panic(0x11d6b60, 0x123d440)
        /usr/local/Cellar/go/1.14/libexec/src/runtime/panic.go:973 +0x396
_/Users/changkun/Desktop/testing/parallel_test.TestA.func1.1(0xc000156360)
        /Users/changkun/Desktop/testing/parallel/main_test.go:13 +0x55
testing.tRunner(0xc000156360, 0x12175d8)
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:992 +0x1ec
created by testing.(*T).Run
        /usr/local/Cellar/go/1.14/libexec/src/testing/testing.go:1043 +0x661
FAIL    _/Users/changkun/Desktop/testing/parallel       0.066s
FAIL

Change https://golang.org/cl/221322 mentions this issue: testing: fix data race between parallel subtests

Does this need to be backported if it's a race in 1.14?

@gopherbot

@gopherbot Please backport to 1.14. This is a regression that was newly introduced in 1.14.

Backport issue(s) opened: #37959 (for 1.14).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://golang.org/wiki/MinorReleases.

Change https://golang.org/cl/224257 mentions this issue: [release-branch.go1.14] testing: fix data race between parallel subtests

[release-branch.go1.14] testing: fix data race between parallel subtests

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testing: data race between parallel panicking and normal subtest #37551

What version of Go are you using (`go version`)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (`go env`)?

What did you do?

What did you expect to see?

What did you see instead?

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testing: data race between parallel panicking and normal subtest #37551

Description

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

Activity

gopherbot commented on Feb 28, 2020

zikaeroh commented on Mar 20, 2020

ianlancetaylor commented on Mar 20, 2020

gopherbot commented on Mar 20, 2020

gopherbot commented on Mar 20, 2020

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?