This crash occurs very frequently on windows platform and is likely preventing the fuzzer phoglund_webrtc_peerconnection from making much progress. Fixing this will allow more bugs to be found.

Marking this bug as a blocker for next Beta release.

If this is incorrect, please add ClusterFuzz-Wrong label and remove the ReleaseBlock-Beta label.

Predator and CL could not provide any possible suspects.

Using Code Search for the file, "gl_fence.cc" suspecting the below Cl might have caused this issue

Suspect CL: https://chromium.googlesource.com/chromium/src/+/3821fdf5c54add24d02adef248a311c293ea0bd0

sadrul@ -- Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Thanks!

The logs contain the following before the null-read:

...
[4844:1016:1109/001040.262:ERROR:angle_platform_impl.cc(47)] reset(614): Could not create additional swap chains or offscreen surfaces, HRESULT: 0x887A0022
[4844:1016:1109/001040.263:ERROR:gl_surface_egl.cc(537)] EGL Driver message (Critical) eglCreateWindowSurface: Context lost.
[4844:1016:1109/001040.264:ERROR:gl_surface_egl.cc(1057)] eglCreateWindowSurface failed with error EGL_CONTEXT_LOST
[4844:1016:1109/001040.264:ERROR:gles2_command_buffer_stub.cc(237)] ContextResult::kSurfaceFailure: Failed to create surface.
[4844:1016:1109/001040.270:ERROR:gl_surface_egl.cc(537)] EGL Driver message (Critical) eglMakeCurrent: Context lost.
[496:5056:1109/001040.272:ERROR:gpu_process_transport_factory.cc(963)] Lost UI shared context.
[4844:1016:1109/001040.549:ERROR:gl_bindings_autogen_gl.cc(13953)] Trying to call glGetIntegerv without current GL context
[4844:1016:1109/001040.549:ERROR:gl_bindings_autogen_gl.cc(13953)] Trying to call glGetString without current GL context
[4844:1016:1109/001040.550:ERROR:gl_bindings_autogen_gl.cc(13953)] Trying to call glGetString without current GL context
[4844:1016:1109/001040.550:ERROR:gl_bindings_autogen_gl.cc(13953)] Trying to call glGetString without current GL context
[4844:1016:1109/001040.550:ERROR:gl_bindings_autogen_gl.cc(13953)] Trying to call glGetString without current GL context
=================================================================
==4844==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000e66 (pc 0x7fff0381a84c bp 0x00507f5f7e60 sp 0x00507f5f62e0 T0)
...

Perhaps angle related?

Looks like a dupe of  issue 897076 

Assigning to Mo in case this is something new.

Yes, this is a dupe of  crbug.com/897076 , but since I closed that already, let's not dupe because there is an action we need to take.

I expect similar things will surface and disappear until we pass in --use-gl=swiftshader to this fuzzer.

phoglund@: can you do that? since you are the owner of this fuzzer

Sure.

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chrome/webrtc-internal/webrtc-signal/+/425000b5508e643e951f5c4772cfc1f47581db48

commit 425000b5508e643e951f5c4772cfc1f47581db48
Author: Patrik Höglund <phoglund@chromium.org>
Date: Mon Nov 19 09:25:33 2018

Friendly ping for an update on this.

Now we run this fuzzer with SwiftShader, the issue should be fixed.

phoglund@: thanks.

Right, I forgot to mark the bug fixed. The fuzzer is deployed since a couple weeks back so we should be good.

ClusterFuzz testcase 5174775275847680 appears to be flaky, updating reproducibility label.

Automatically applying components based on crash stacktrace and information from OWNERS files.

If this is incorrect, please apply the Test-Predator-Wrong-Components label.