Hi kbr@ it seems like a couple of these context lost test are a bit flaky. Usually it's just the WebGLUnblockedAfterUserInitiatedReload, but sometimes the  gpu_tests.context_lost_integration_test.ContextLostIntegrationTest.ContextLost_WebGLBlockedAfterJSNavigation test will also fail.

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Mac%20Retina%20Release%20%28AMD%29/47145

I assigned the bug to you because you have made the most changes to the context_lost_integration_test.py, so I figured that you might have a better idea of the cause.

Thanks for reporting. There's a crash inside the compositor which is causing these test failures. From this log:
https://chromium-swarm.appspot.com/task?id=418ee327f571da10&refresh=10&show_raw=1

from this run:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Mac%20Retina%20Release%20%28AMD%29/47150

  	Operating system: Mac OS X
  	                  10.13.6 17G65
  	CPU: amd64
  	     family 6 model 70 stepping 1
  	     8 CPUs
  	
  	GPU: UNKNOWN
  	
  	Crash reason:  EXC_BREAKPOINT / EXC_I386_BPT
  	Crash address: 0x10b78cd11
  	Process uptime: 3 seconds
  	
  	Thread 0 (crashed)
  	 0  Chromium Framework!__ZN4base5debug13BreakDebuggerEv + 0x11
  	    rax = 0x00007fd4c400fa3e   rdx = 0x00007fd4c400fa3e
  	    rcx = 0x0000000000000091   rbx = 0x0000000000000091
  	    rsi = 0x0000000000000493   rdi = 0x00000001139ed8ec
  	    rbp = 0x00007ffeebc9d090   rsp = 0x00007ffeebc9d090
  	     r8 = 0x00007fd4c400facf    r9 = 0x0000000000001598
  	    r10 = 0x00007fd4c400facf   r11 = 0x000000010b7cf260
  	    r12 = 0x00007fd4bff02a30   r13 = 0x00007fd4c400facf
  	    r14 = 0x00007ffeebc9d9b0   r15 = 0x00007ffeebc9d9a8
  	    rip = 0x000000010b78cd11
  	    Found by: given as instruction pointer in context
  	 1  Chromium Framework!__ZN7logging10LogMessageD2Ev + 0x900
  	    rbp = 0x00007ffeebc9d990   rsp = 0x00007ffeebc9d0a0
  	    rip = 0x000000010b68c400
  	    Found by: previous frame's frame pointer
  	 2  Chromium Framework!__ZN2cc13LayerTreeHost23SetViewportSizeAndScaleERKN3gfx4SizeEfRKN3viz24LocalSurfaceIdAllocationE + 0x1f0
  	    rbp = 0x00007ffeebc9daf0   rsp = 0x00007ffeebc9d9a0
  	    rip = 0x000000010d1f56b0
  	    Found by: previous frame's frame pointer
  	 3  Chromium Framework!__ZN7content12RenderWidget26UpdateSurfaceAndScreenInfoERKN3viz24LocalSurfaceIdAllocationERKN3gfx4SizeERKNS_10ScreenInfoE + 0x15c
  	    rbp = 0x00007ffeebc9dd50   rsp = 0x00007ffeebc9db00
  	    rip = 0x0000000111b5ed9c
  	    Found by: previous frame's frame pointer
  	 4  Chromium Framework!__ZN7content12RenderWidget27SynchronizeVisualPropertiesERKNS_16VisualPropertiesE + 0x136
  	    rbp = 0x00007ffeebc9df20   rsp = 0x00007ffeebc9dd60
  	    rip = 0x0000000111b679d6
  	    Found by: previous frame's frame pointer
  	 5  Chromium Framework!__ZN7content12RenderWidget29OnSynchronizeVisualPropertiesERKNS_16VisualPropertiesE + 0x200
  	    rbp = 0x00007ffeebc9e200   rsp = 0x00007ffeebc9df30
  	    rip = 0x0000000111b64300
  	    Found by: previous frame's frame pointer
  	 6  Chromium Framework!__ZN3IPC8MessageTI42WidgetMsg_SynchronizeVisualProperties_MetaNSt3__15tupleIJN7content16VisualPropertiesEEEEvE8DispatchINS4_12RenderWidgetES9_vMS9_FvRKS5_EEEbPKNS_7MessageEPT_PT0_PT1_T2_ + 0x75
  	    rbp = 0x00007ffeebc9e360   rsp = 0x00007ffeebc9e210
  	    rip = 0x0000000111b5fe25
  	    Found by: previous frame's frame pointer
  	 7  Chromium Framework!__ZN7content12RenderWidget17OnMessageReceivedERKN3IPC7MessageE + 0x1cc
  	    rbp = 0x00007ffeebc9e4d0   rsp = 0x00007ffeebc9e370
  	    rip = 0x0000000111b5f35c
  	    Found by: previous frame's frame pointer
  	 8  Chromium Framework!__ZN7content14RenderViewImpl17OnMessageReceivedERKN3IPC7MessageE + 0x641
  	    rbp = 0x00007ffeebc9e760   rsp = 0x00007ffeebc9e4e0
  	    rip = 0x0000000111b56db1
  	    Found by: previous frame's frame pointer
  	 9  Chromium Framework!__ZN3IPC13MessageRouter12RouteMessageERKNS_7MessageE + 0x92
  	    rbp = 0x00007ffeebc9e8b0   rsp = 0x00007ffeebc9e770
  	    rip = 0x000000010c08f272
  	    Found by: previous frame's frame pointer
  	10  Chromium Framework!__ZN3IPC13MessageRouter17OnMessageReceivedERKNS_7MessageE + 0x8d
  	    rbp = 0x00007ffeebc9ea00   rsp = 0x00007ffeebc9e8c0
  	    rip = 0x000000010c08f1cd
  	    Found by: previous frame's frame pointer
  	11  Chromium Framework!__ZN7content15ChildThreadImpl17OnMessageReceivedERKN3IPC7MessageE + 0x9f
  	    rbp = 0x00007ffeebc9eb50   rsp = 0x00007ffeebc9ea10
  	    rip = 0x000000010f46d0ff
  	    Found by: previous frame's frame pointer
  	12  Chromium Framework!__ZN3IPC12ChannelProxy7Context17OnDispatchMessageERKNS_7MessageE + 0x81
  	    rbp = 0x00007ffeebc9eb90   rsp = 0x00007ffeebc9eb60
  	    rip = 0x000000010c07b951
  	    Found by: previous frame's frame pointer
  	13  Chromium Framework!__ZN4base8internal7InvokerINS0_9BindStateIMN3IPC12ChannelProxy7ContextEFvRKNS3_7MessageEEJ13scoped_refptrIS5_ES6_EEEFvvEE3RunEPNS0_13BindStateBaseE + 0x8b
  	    rbp = 0x00007ffeebc9ecf0   rsp = 0x00007ffeebc9eba0
  	    rip = 0x000000010c07e15b
  	    Found by: previous frame's frame pointer
  	14  Chromium Framework!__ZN4base5debug13TaskAnnotator7RunTaskEPKcPNS_11PendingTaskE + 0x131
  	    rbp = 0x00007ffeebc9eeb0   rsp = 0x00007ffeebc9ed00
  	    rip = 0x000000010b675381
  	    Found by: previous frame's frame pointer
  	15  Chromium Framework!__ZN4base16sequence_manager8internal20ThreadControllerImpl6DoWorkENS2_8WorkTypeE + 0x379
  	    rbp = 0x00007ffeebc9f170   rsp = 0x00007ffeebc9eec0
  	    rip = 0x000000010b720759
  	    Found by: previous frame's frame pointer
  	16  Chromium Framework!__ZN4base8internal7InvokerINS0_9BindStateIMNS_16sequence_manager8internal20ThreadControllerImplEFvNS5_8WorkTypeEEJNS_7WeakPtrIS5_EES6_EEEFvvEE3RunEPNS0_13BindStateBaseE + 0xbb
  	    rbp = 0x00007ffeebc9f2d0   rsp = 0x00007ffeebc9f180
  	    rip = 0x000000010b72251b
  	    Found by: previous frame's frame pointer



danakj, weiliangc, were there some refactorings in this area that could have provoked this crash in the event of a lost context due to a GPU process crash? Could you please help triage / reassign? Thank you!

This is a DCHECK/CHECK failing:

  	Crash reason:  EXC_BREAKPOINT / EXC_I386_BPT
  	Crash address: 0x10b78cd11

Probably this one again/still:

#if defined(OS_MACOSX)
    // TODO(ccameron): This check is not valid on Aura or Mus yet, but should
    // be.
    CHECK(!has_pushed_local_surface_id_from_parent_ ||
          new_local_surface_id_request_ ||
          !local_surface_id_allocation_from_parent_.IsValid());
#endif

Thanks danakj@ for triaging this and finding the duplicate bug. I thought I'd seen it but couldn't find it with bug search.

No problem, for reference I remembered copy pasting in that code so i searched for a snippet from the comment to find it.