Assigning to the concern owner from Predator results --
Regression information is not available. The result is the blame information. 

Author: John Bauman
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/894018228b0e0bdbd7aa7e8f47d4a9458789ca82
Time: Tue May 06 15:04:28 2014 -0400
The CL last changed line 1072 of file Surface.cpp, which is stack frame 0. 

Author: John Bauman
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/19bac1e08be200c31efd26f0f5fd144c9b3eefd3
Time: Tue May 06 15:23:49 2014 -0400
The CL last changed line 1420 of file Surface.cpp, which is stack frame 1. 

Author: Nicolas Capens
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/0bac285a78df6a6d7a6b68784748b92805420ffb
Time: Sat May 07 06:09:58 2016 -0400
The CL last changed line 485 of file Surface.hpp, which is stack frame 2. 

Author: Alexis Hetu
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/75b650f0e501750ae0ba66a435741731905dffc1
Time: Thu Nov 19 17:40:15 2015 -0500
The CL last changed line 152 of file Blitter.cpp, which is stack frame 3. 

Author: Alexis Hetu
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/75b650f0e501750ae0ba66a435741731905dffc1
Time: Thu Nov 19 17:40:15 2015 -0500
The CL last changed line 142 of file Blitter.cpp, which is stack frame 4. 

Author: Alexis Hetu
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/b9dda64e0e31dc5ac3eb7a19948062385a097cdb
Time: Thu Oct 06 11:25:32 2016 -0400
The CL last changed line 212 of file Renderer.cpp, which is stack frame 5. 

Author: Nicolas Capens
Project: chromium-swiftshader
Changelist: https://swiftshader.googlesource.com/SwiftShader.git/+/0bac285a78df6a6d7a6b68784748b92805420ffb
Time: Sat May 07 06:09:58 2016 -0400
The CL last changed line 3241 of file Context.cpp, which is stack frame 6.

Suspecting Commit#
https://swiftshader.googlesource.com/SwiftShader.git/+/75b650f0e501750ae0ba66a435741731905dffc1

@sugoi -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

This appears to be another manifestation of  Issue 710753  and  Issue 710822 .

Race happens in BackoffLock::isLocked(), same as  Issue 710753  but called from a different location / different lock object.

ClusterFuzz has detected this issue as fixed in range 464734:464738.

Detailed report: https://clusterfuzz.com/testcase?key=5361075651608576

Fuzzer: ochang_domfuzzer
Job Type: linux_tsan_chrome_mp
Platform Id: linux

Crash Type: Data race WRITE 4
Crash Address: 0x7b4000002374
Crash State:
  sw::Surface::Buffer::lockRect
  sw::Surface::lockInternal
  sw::Blitter::blitReactor
  
Sanitizer: thread (TSAN)

Fixed: https://clusterfuzz.com/revisions?job=linux_tsan_chrome_mp&range=464734:464738

Reproducer Testcase: https://clusterfuzz.com/download/AMIfv95_CLtmpKPd8Cz5WH3a7aBfjsIZ5iwRoZpYbJWZhQQdyC_AuXhvoUpTaNPCapey1PpB-9mi-Xugt7ilukHZAaWqwc3yHjSLpEd2l7hKmMJtCkLYsDc03HCwPLbRXvpg0W7VdSjihJUXcUyMUPaKpEsso0QgTRcqZdNLmA4uK4C7lJgV-8KNouO1SySUeeT6ncZYqgC6nrXb29DPtO4zk0dg-yD44UNOxRyCTuP1pO-RKLv-XGK1k9e4fN6MXrQ-IQtgXFKS0KyiHlKBuw-8R8EIAIUlhIERjlZh40QSXGqHRarhGAwix4e7eR4Y94Ijj-3axfYoMkBblN_zZR0vboj6g0NGMKOjGbHHpcfuk5SusXYaHsw?testcase_id=5361075651608576


See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.