Does runtime.RaceDisable not work in non-std library ?

[nea...@gmail.com]

Hi,

When I copy the sync.Pool's source code in a repo, and using `//go:linkname` link those runtime functions manually.

When I run `go test -race`, it reports `DATA RACE`.

But the sync.Pool with the same test case does not report  `DATA RACE`.

Does runtime.RaceDisable not work in non-std library ?

[Ian Lance Taylor]

It should work. I think you'll have to show us your code.

Ian

[nea...@gmail.com]

Thanks for your attention.

Here is the code : https://gist.github.com/lrita/efa8c4ae555b4b7cceee29b4ed819652

When I run `go test -v -race -count=10 .`  `TestSyncAPI` reports DATA RACE, `TestSyncAPI2` not reports. 

在 2018年8月22日星期三 UTC+8下午10:34:35，Ian Lance Taylor写道：

[Ian Lance Taylor]

On Thu, Aug 23, 2018 at 12:43 AM, <buaa...@gmail.com> wrote:
> package main
>
> import "runtime"
>
> var a int
>
> func calc() {
> for i := 0; i < 10; i++ {
> go func() {
> for {
> runtime.RaceDisable()
> a++
> runtime.RaceEnable()
> }
> }()
>
> }
> }
>
> func main() {
> calc()
> }
>
> go run -race a.go

Thanks for the example. As the docs for runtime.RaceDisable say, it
only applies to synchronization events, like mutex locks. It doesn't
apply to memory accesses.

Ian

> 在 2018年8月22日星期三 UTC+8下午10:34:35，Ian Lance Taylor写道：
>>

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[nea...@gmail.com]

Hi lan,

The sync.Pool has memory accesses in per-p private storage. Why it not reports `DATA RACE`, but it reports when I copy those code outside stdlib?

I'm confused about this, or there is something wrong in https://gist.github.com/lrita/efa8c4ae555b4b7cceee29b4ed819652 
Thanks.

在 2018年8月24日星期五 UTC+8上午4:36:06，Ian Lance Taylor写道：

[Dave Cheney]

Hi,

Can you please do two things to help with this error report.

1. Please include the entire data race report -- we need this to match up the line with the source code you've provided in the gist

2. Please double check that you are not copying a your sync.Pool type by value, this can happen if you have a type declared on sync.Pool, not *sync.Pool, or it could happen if you do something like this

var x sync.Pool

y := x

Thanks

Dave

[nea...@gmail.com]

Hi Dave,

1. the report:

> go version

go version go1.10 darwin/amd64

> go test -v -race -count=5 .

=== RUN   TestSyncAPI

==================

WARNING: DATA RACE

Read at 0x00c4200ca080 by goroutine 8:

  _/Users/yanqing11/test/go/sync1.(*Pool).Put()

      /Users/yanqing11/test/go/sync1/pool.go:108 +0xe8

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func2()

      /Users/yanqing11/test/go/sync1/pool_test.go:18 +0x50

Previous write at 0x00c4200ca080 by goroutine 7:

  _/Users/yanqing11/test/go/sync1.(*Pool).Put()

      /Users/yanqing11/test/go/sync1/pool.go:109 +0x2ad

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func1()

      /Users/yanqing11/test/go/sync1/pool_test.go:14 +0x5e

Goroutine 8 (running) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:17 +0x129

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

Goroutine 7 (finished) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:12 +0xfd

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

==================

==================

WARNING: DATA RACE

Write at 0x00c4200ca090 by goroutine 8:

  _/Users/yanqing11/test/go/sync1.(*Pool).Put()

      /Users/yanqing11/test/go/sync1/pool.go:115 +0x206

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func2()

      /Users/yanqing11/test/go/sync1/pool_test.go:18 +0x50

Previous read at 0x00c4200ca090 by goroutine 7:

  _/Users/yanqing11/test/go/sync1.(*Pool).Get()

      /Users/yanqing11/test/go/sync1/pool.go:141 +0x1ee

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func1()

      /Users/yanqing11/test/go/sync1/pool_test.go:13 +0x38

Goroutine 8 (running) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:17 +0x129

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

Goroutine 7 (finished) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:12 +0xfd

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

==================

==================

WARNING: DATA RACE

Read at 0x00c4200ce000 by goroutine 9:

  _/Users/yanqing11/test/go/sync1.(*Pool).getSlow()

      /Users/yanqing11/test/go/sync1/pool.go:175 +0x17a

  _/Users/yanqing11/test/go/sync1.(*Pool).Get()

      /Users/yanqing11/test/go/sync1/pool.go:148 +0x243

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func3()

      /Users/yanqing11/test/go/sync1/pool_test.go:23 +0x38

Previous write at 0x00c4200ce000 by goroutine 8:

  _/Users/yanqing11/test/go/sync1.(*Pool).Put()

      /Users/yanqing11/test/go/sync1/pool.go:115 +0x1c6

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func2()

      /Users/yanqing11/test/go/sync1/pool_test.go:18 +0x50

Goroutine 9 (running) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:22 +0x155

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

Goroutine 8 (finished) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:17 +0x129

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

==================

--- FAIL: TestSyncAPI (0.00s)

testing.go:730: race detected during execution of test

=== RUN   TestSyncAPI2

--- PASS: TestSyncAPI2 (0.00s)

=== RUN   TestSyncAPI

--- PASS: TestSyncAPI (0.00s)

=== RUN   TestSyncAPI2

--- PASS: TestSyncAPI2 (0.00s)

=== RUN   TestSyncAPI

--- PASS: TestSyncAPI (0.00s)

=== RUN   TestSyncAPI2

--- PASS: TestSyncAPI2 (0.00s)

=== RUN   TestSyncAPI

==================

WARNING: DATA RACE

Read at 0x00c42010a380 by goroutine 36:

  _/Users/yanqing11/test/go/sync1.(*Pool).Get()

      /Users/yanqing11/test/go/sync1/pool.go:136 +0x5c

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func3()

      /Users/yanqing11/test/go/sync1/pool_test.go:23 +0x38

Previous write at 0x00c42010a380 by goroutine 34:

  _/Users/yanqing11/test/go/sync1.(*Pool).Put()

      /Users/yanqing11/test/go/sync1/pool.go:109 +0x2ad

  _/Users/yanqing11/test/go/sync1.TestSyncAPI.func1()

      /Users/yanqing11/test/go/sync1/pool_test.go:14 +0x5e

Goroutine 36 (running) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:22 +0x155

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

Goroutine 34 (finished) created at:

  _/Users/yanqing11/test/go/sync1.TestSyncAPI()

      /Users/yanqing11/test/go/sync1/pool_test.go:12 +0xfd

  testing.tRunner()

      /Users/yanqing11/dev/go/src/testing/testing.go:777 +0x16d

==================

--- FAIL: TestSyncAPI (0.00s)

testing.go:730: race detected during execution of test

=== RUN   TestSyncAPI2

--- PASS: TestSyncAPI2 (0.00s)

=== RUN   TestSyncAPI

--- PASS: TestSyncAPI (0.00s)

=== RUN   TestSyncAPI2

--- PASS: TestSyncAPI2 (0.00s)

FAIL

FAIL _/Users/yanqing11/test/go/sync1 0.025s

2. the test case using a pointer of Pool, the test case code is also in the gist. https://gist.github.com/lrita/efa8c4ae555b4b7cceee29b4ed819652#file-pool_test-go 

Thanks for your reply.

在 2018年8月24日星期五 UTC+8下午12:41:17，Dave Cheney写道：

[Ian Lance Taylor]

On Fri, Aug 24, 2018 at 12:28 AM, <nea...@gmail.com> wrote:
>
>> go test -v -race -count=5 .
> === RUN TestSyncAPI
> ==================
> WARNING: DATA RACE
> Read at 0x00c4200ca080 by goroutine 8:
> _/Users/yanqing11/test/go/sync1.(*Pool).Put()
> /Users/yanqing11/test/go/sync1/pool.go:108 +0xe8
> _/Users/yanqing11/test/go/sync1.TestSyncAPI.func2()
> /Users/yanqing11/test/go/sync1/pool_test.go:18 +0x50
>
> Previous write at 0x00c4200ca080 by goroutine 7:
> _/Users/yanqing11/test/go/sync1.(*Pool).Put()
> /Users/yanqing11/test/go/sync1/pool.go:109 +0x2ad
> _/Users/yanqing11/test/go/sync1.TestSyncAPI.func1()
> /Users/yanqing11/test/go/sync1/pool_test.go:14 +0x5e

These race reports are data races on memory accesses, and as such are
not affect by runtime.RaceDisable.

I don't know what the problem is here but I don't think it's related
to RaceDisable.

Ian

[nea...@gmail.com]

Thanks a lot.

在 2018年8月25日星期六 UTC+8上午1:32:12，Ian Lance Taylor写道：

[nea...@gmail.com]

According to https://github.com/golang/go/blob/7a6ccece877232fc58872c85fdf0718629b83d91/src/cmd/compile/internal/gc/racewalk.go#L45-L47 , the compile does not insert data race detecting code in package "sync".

在 2018年8月22日星期三 UTC+8下午6:25:24，nea...@gmail.com写道：