Predator and CL could not provide any possible suspects.
Using the code search for the file, “checks.cc” assigning to concern owner from GIT blame.
Suspecting Commit#
https://chromium.googlesource.com/external/webrtc/trunk/webrtc.git/+/eac9d2aff9b97d1de43cebb0fcaee90f6dd49240
@kjellander -- Could you please look into this issue, kindly reassign if it has nothing to do with your changes.
Thank You.

Assigning to pbos@ who added the check

Please retriage, this just means that a thread couldn't be created, and as webrtc has no way to mitigate that (global worker thread etc), we do a check, panic and quit.

AI would probably be to figure out why the thread creation failed (maybe this test creates 10k PeerConnections, etc.

The testcase is really simple:

<script>
        var __v_30 = function () {
            pc = new webkitRTCPeerConnection();
        };
        for (var __v_40 = 0; __v_40 < 1000; __v_40++)
            __v_30();
</script>

ClusterFuzz has detected this issue as fixed in range 525690:525711.

Detailed report: https://clusterfuzz.com/testcase?key=5818808479776768

Fuzzer: inferno_layout_test_unmodified
Job Type: mac_asan_chrome
Platform Id: mac

Crash Type: CHECK failure
Crash Address: 
Crash State:
  0 == pthread_create(&thread_, &attr, &StartThread, this) in platform_thread.cc
  rtc::FatalMessage::~FatalMessage
  rtc::FatalMessage::~FatalMessage
  
Sanitizer: address (ASAN)

Fixed: https://clusterfuzz.com/revisions?job=mac_asan_chrome&range=525690:525711

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5818808479776768

See https://github.com/google/clusterfuzz-tools for more information.

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