Find it and CL did not provide any possible suspects.
Assigning to the concern owner from Code Search using the file, "AudioBufferSourceNode.cpp"

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/86a60cb0983a8bd9689d5c0ce7684f04799ada02

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

rtoy@ is probably a better owner.

I can't reproduce this locally, but I'm guessing it's caused by accessing m_didSetLooping.  The audio thread reads this (very often) and the main thread sets it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/310673a6eca24e30371c29593b4385fd3983ad1d

commit 310673a6eca24e30371c29593b4385fd3983ad1d
Author: rtoy <rtoy@chromium.org>
Date: Wed Jan 04 02:56:22 2017

Use atomics when accessing m_didSetLooping

Add setter and getter methods for accessing m_didSetLooping so that we
can access it atomically. The audio thread was reading this while the
main thread could be writing it.

Manually verified the test case from the bug that this fix works. (Need to reload the page a few times to trigger the original bug.)

BUG= 676874 
TEST=

Review-Url: https://codereview.chromium.org/2615463002
Cr-Commit-Position: refs/heads/master@{#441304}

[modify] https://crrev.com/310673a6eca24e30371c29593b4385fd3983ad1d/third_party/WebKit/Source/modules/webaudio/AudioBufferSourceNode.cpp
[modify] https://crrev.com/310673a6eca24e30371c29593b4385fd3983ad1d/third_party/WebKit/Source/modules/webaudio/AudioBufferSourceNode.h

ClusterFuzz has detected this issue as fixed in range 440945:440947.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=6721155726835712

Fuzzer: inferno_twister_custom_bundle
Job Type: linux_tsan_chrome_mp
Platform Id: linux

Crash Type: Data race READ 1
Crash Address: 0x7b4400002cb1
Crash State:
  blink::AudioBufferSourceHandler::handleStoppableSourceNode
  blink::BaseAudioContext::handleStoppableSourceNodes
  blink::BaseAudioContext::handlePreRenderTasks
  
Sanitizer: thread (TSAN)

Regressed: https://cluster-fuzz.appspot.com/revisions?job=linux_tsan_chrome_mp&range=440655:440657
Fixed: https://cluster-fuzz.appspot.com/revisions?job=linux_tsan_chrome_mp&range=440945:440947

Minimized Testcase (0.19 Kb):
Download: https://cluster-fuzz.appspot.com/download/AMIfv94snAxbTtVfQccRCD9uoE90_ntCVLIf1KVavJEc9JFNmoFqMuUFU1-Bz3S67W7XmRK3YALq06efpPzR1UoNeqKN0PpYiiyp0BpgJY1G8ceQXSS1k13oc2lPLohQPh40Xed6QjE5RxC_RMnb1VEUZ1nKTipwMw?testcase_id=6721155726835712
<script>
;
 o2 = new window.AudioContext(); 
 o3 = o2.createBufferSource(); 
 o3.start() 
try { o3.buffer = function anonymous() {
}(); } catch(e) {; }
 o3.loop = false; 
 setInterval() 
</script>


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.

ClusterFuzz testcase 6721155726835712 is verified as fixed, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.