Bug 31390 - Debugger crashing with error
Summary: Debugger crashing with error
Alias: None
Product: iOS
Classification: Xamarin
Component: Debugger ()
Version: XI 8.10
Hardware: PC Mac OS
: High major
Target Milestone: Untriaged
Assignee: Zoltan Varga
Depends on:
Reported: 2015-06-25 17:40 UTC by David Hathaway
Modified: 2015-06-29 05:25 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

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Comment 3 Rolf Bjarne Kvinge [MSFT] 2015-06-26 11:28:22 UTC
Zoltan, can you have a look?

I can reproduce the crash with current stable ( with both simulator (both i386 and x86_64) and device.

With maccore master I can only reproduce the crash with the simulators, not on device.

Unfortunately the crash report isn't very helpful (to me at least), and attaching a debugger doesn't help much since it'll run into the expected breakpoint signals.

Crash report (using maccore/master): https://gist.github.com/rolfbjarne/0dd048aa65ce7fcbf58b
Comment 4 Zoltan Varga 2015-06-26 16:35:36 UTC
That library seems to install its own signal handlers, which is probably whats causing the crash:

* thread #1: tid = 0x16b275, 0x00000001966730f0 libsystem_c.dylib`sigaction, queue = 'com.apple.main-thread', stop reason = breakpoint 1.2
  * frame #0: 0x00000001966730f0 libsystem_c.dylib`sigaction
    frame #1: 0x0000000100456a5c iOSSample`-[PLCrashSignalHandler registerHandlerWithSignal:error:] + 272
    frame #2: 0x0000000100456bfc iOSSample`-[PLCrashSignalHandler registerHandlerForSignal:callback:context:error:] + 40
    frame #3: 0x0000000100459954 iOSSample`-[PLCrashReporter enableCrashReporterAndReturnError:] + 780
    frame #4: 0x0000000100437ebc iOSSample`-[ADEumCrashReporter enableCrashReporting] + 104
    frame #5: 0x00000001004558b4 iOSSample`-[ADEumCrashReportingFeature init] + 204
    frame #6: 0x00000001004557ac iOSSample`-[ADEumCrashReportingFeatureFactory createFeature] + 32

The reason this doesn't happen on cycle6 is that we no longer use signals to implement debugging on arm64.
Comment 5 Rolf Bjarne Kvinge [MSFT] 2015-06-29 05:25:50 UTC
Zoltan is right, the library is installing it's own crash reporter, which interferes with our debugger.

The workaround is explained here: http://stackoverflow.com/a/14499336/183422