Predator and CL could not provide any possible suspects.
Using Code Search for the file, "lock_impl_posix.cc" assigning to the concern owner who might be related.

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/05b564e44b5289fa86ee281eb308f7437ec3299e

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

The CHECK was temporary to catch Lock misuse. It's been reverted.

This did however reveal a likely lock-order inversion, but it's not clear yo me whether the bug is in the bindings or in the fuzzer's use of the bindings.

I will take a look.

It seems the message in MultiplexRouter::MessageWrapper constains ScopedInterfaceEndpointHandle, which should never happen after my recent change. Hmm...

Automatically applying components based on information from OWNERS files. If this seems incorrect, please apply the Test-Predator-Wrong-Components label.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4a917c60a906fbaa1541711af8009099fc6292ff

commit 4a917c60a906fbaa1541711af8009099fc6292ff
Author: Yuzhu Shen <yzshen@chromium.org>
Date: Tue Oct 17 03:48:49 2017

Mojo C++ bindings: avoid destroying ScopedInterfaceEndpointHandle under MultiplexRouter's lock.

BUG= 757187 

Change-Id: If2513dfdd287f0c06df917bd2c0b87cf6e0ea539
Reviewed-on: https://chromium-review.googlesource.com/722029
Reviewed-by: Oliver Chang <ochang@chromium.org>
Commit-Queue: Yuzhu Shen <yzshen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509269}
[modify] https://crrev.com/4a917c60a906fbaa1541711af8009099fc6292ff/mojo/public/cpp/bindings/lib/multiplex_router.cc

ClusterFuzz has detected this issue as fixed in range 509258:509279.

Detailed report: https://clusterfuzz.com/testcase?key=5164140829343744

Fuzzer: libFuzzer_mojo_parse_message_fuzzer
Job Type: libfuzzer_chrome_asan_debug
Platform Id: linux

Crash Type: CHECK failure
Crash Address: 
Crash State:
  rv == 0Resource deadlock avoided in lock_impl_posix.cc
  base::internal::LockImpl::Lock
  base::Lock::Acquire
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan_debug&range=495780:495802
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_asan_debug&range=509258:509279

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5164140829343744

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.md 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 5164140829343744 is verified as fixed, so closing issue as verified.

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