The desktopui_MusLogin autotest is being flaky on a subset of boards in the lab. I've pulled a stack trace from failing squawks R61-9634.0.0.

Operating system: Linux
                  0.0.0 Linux 4.4.70-09706-gd8c4b682591e #1 SMP PREEMPT Fri Jun 9 11:03:18 PDT 2017 x86_64
CPU: amd64
     family 6 model 55 stepping 8
     2 CPUs

GPU: UNKNOWN

Crash reason:  SIGTRAP
Crash address: 0x0
Process uptime: not available

 0  chrome!aura::(anonymous namespace)::OnAckMustSucceed(bool) + 0x7
 1  chrome!ui::mojom::WindowManagerClient_SetDisplayConfiguration_ForwardToCallback::Accept(mojo::Message*) + 0xa6
 2  chrome!mojo::InterfaceEndpointClient::HandleValidatedMessage(mojo::Message*) + 0x2c9
 3  chrome!mojo::internal::MultiplexRouter::ProcessIncomingMessage(mojo::Message*, mojo::internal::MultiplexRouter::ClientCallBehavior, base::SingleThreadTaskRunner*) + 0x1bb
 4  chrome!mojo::internal::MultiplexRouter::Accept(mojo::Message*) + 0xb4
 5  chrome!mojo::Connector::ReadSingleMessage(unsigned int*) + 0x152
 6  chrome!mojo::Connector::ReadAllAvailableMessages() + 0x61
 7  chrome!mojo::SimpleWatcher::OnHandleReady(int, unsigned int) + 0xaa
 8  chrome!base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) + 0x101
 9  chrome!base::MessageLoop::RunTask(base::PendingTask*) + 0x1a2
10  chrome!base::MessageLoop::DoWork() + 0x40c
11  chrome!base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) + 0x1a2
12  chrome!base::RunLoop::Run() + 0x40
13  chrome!ChromeBrowserMainParts::MainMessageLoopRun(int*) + 0xc2
14  chrome!content::BrowserMainLoop::RunMainMessageLoopParts() + 0x44
15  chrome!content::BrowserMainRunnerImpl::Run() + 0x12
16  chrome!content::BrowserMain(content::MainFunctionParams const&) + 0x8c
17  chrome!content::ContentMainRunnerImpl::Run() + 0x184
18  chrome!service_manager::Main(service_manager::MainParams const&) + 0x6e0
19  chrome!content::ContentMain(content::ContentMainParams const&) + 0x51
20  chrome!ChromeMain + 0x9c
21  libc-2.23.so!__libc_start_main [libc-start.c : 289 + 0x1a]
22  chrome!_start + 0x29
23  0x7ffd2c44c258

It would appear that ui::ws::DisplayManager::SetDisplayConfiguration() returns false for some reason. When the callback with false reaches ash it's a fatal error and ash crashes.

There are log statements in SetDisplayConfiguration() but they're all DVLOG(1) so not included in the auto builds. The log statements should probably be LOG(ERROR) since returning false from SetDisplayConfiguration() is a serious failure.
 

Deleted: minidump.txt 143 KB

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