leadership: avoid potential data race

[lhy1024]

What problem does this PR solve?

Issue Number: Close #6635

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• JmPotato
• rleungx

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[JmPotato]

LGTM. Though It would be better if it could be changed to RWLock.

[lhy1024]

LGTM. Though It would be better if it could be changed to RWLock.

It also write, from #6635

Write at 0x00c0120fc100 by goroutine 925857:
  sync/atomic.CompareAndSwapInt32()
      /usr/lib/go/src/runtime/race_amd64.s:310 +0xb
  sync/atomic.CompareAndSwapInt32()
      <autogenerated>:1 +0x1e
  context.(*cancelCtx).cancel()
      /usr/lib/go/src/context/context.go:460 +0xbd
  context.WithCancel.func1()
      /usr/lib/go/src/context/context.go:240 +0x54
  github.com/tikv/pd/pkg/election.(*Leadership).Reset()
      /home/lhy1024/pd/pkg/election/leadership.go:234 +0xb2
  github.com/tikv/pd/pkg/member.(*EmbeddedEtcdMember).ResetLeader()
      /home/lhy1024/pd/pkg/member/member.go:262 +0x3d
  github.com/tikv/pd/tests.(*TestServer).ResignLeader()
      /home/lhy1024/pd/tests/cluster.go:190 +0xee
  github.com/tikv/pd/tests/integrations/tso.TestMixedTSODeployment.func2()
      /home/lhy1024/pd/tests/integrations/tso/client_test.go:446 +0x127

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.08 🎉

Comparison is base (0934e64) 74.52% compared to head (600369e) 74.60%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6636      +/-   ##
==========================================
+ Coverage   74.52%   74.60%   +0.08%     
==========================================
  Files         417      417              
  Lines       43056    43060       +4     
==========================================
+ Hits        32086    32124      +38     
+ Misses       8113     8087      -26     
+ Partials     2857     2849       -8     

Flag	Coverage Δ
unittests	74.60% <100.00%> (+0.08%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/election/leadership.go	88.11% <100.00%> (+2.55%)	⬆️

... and 27 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[rleungx]

Do we need to cherry pick?

[lhy1024]

Do we need to cherry pick?

Yes.

For LTS 6.5, we only use Reset in member.ResetLeader and allocatorGroup.leadership, Reset of the former is not called anywhere, the latter is not called Keep.

So only need to pick 7.1 and 7.2

[lhy1024]

/merge

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 600369e

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #6638.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.2: #6639.

[rleungx]

Do we need to cherry pick?

Yes.

For LTS 6.5, we only use Reset in member.ResetLeader and allocatorGroup.leadership, Reset of the former is not called anywhere, the latter is not called Keep.

So only need to pick 7.1 and 7.2

Is #6668 related to this PR?

[lhy1024]

Do we need to cherry pick?

Yes.
For LTS 6.5, we only use Reset in member.ResetLeader and allocatorGroup.leadership, Reset of the former is not called anywhere, the latter is not called Keep.
So only need to pick 7.1 and 7.2

Is #6668 related to this PR?

Yes, this is the same problem. Previously I used find reference in vscode and didn't find a call here as well, I will pick this pr to an older version. It is introduced by #4044

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #6702.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #6701.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #6703.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.3: #6704.