Bug 45379 - SGEN Error - 100% Reproducible
Summary: SGEN Error - 100% Reproducible
Alias: None
Product: iOS
Classification: Xamarin
Component: Mono runtime / AOT compiler ()
Version: XI 10.0 (iOS10)
Hardware: PC Mac OS
: --- normal
Target Milestone: 10.2.1 (C8SR1)
Assignee: Zoltan Varga
Depends on:
Reported: 2016-10-13 18:28 UTC by richard
Modified: 2016-10-31 17:21 UTC (History)
5 users (show)

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

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Description richard 2016-10-13 18:28:05 UTC
Getting this 100% reproducible crash on both devices and simulator.

Thread finished:  #16
2016-10-07 15:52:39.979 iCropTrakApp[62974:3108193] error: * Assertion: should not be reached at /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/external/mono/mono/sgen/sgen-scan-object.h:90
ERROR /BuildRoot/Library/Caches/com.apple.xbs/Sources/VectorKit_Sim/VectorKit-1228. 1763: InfoLog SolidRibbonShader:
ERROR /BuildRoot/Library/Caches/com.apple.xbs/Sources/VectorKit_Sim/VectorKit-1228. 1764: WARNING: Output of vertex shader 'v_gradient' not read by fragment shader

ERROR /BuildRoot/Library/Caches/com.apple.xbs/Sources/VectorKit_Sim/VectorKit-1228. 1763: InfoLog TrafficCasingShader:
ERROR /BuildRoot/Library/Caches/com.apple.xbs/Sources/VectorKit_Sim/VectorKit-1228. 1764: WARNING: 0:27: Overflow in implicit constant conversion, minimum range for lowp float is (-2,2)

Believe this is relatively new - as customer has not not changed - but on switch to version of Xamarin/Mono/IOS as below this happens everytime.

Xararmin info:

=== Xamarin Studio Business ===

Version 6.1.1 (build 15)
Installation UUID: 06e8ed9b-6208-476a-a22a-ebeb3b94553b
	Mono 4.6.1 (mono-4.6.0-branch-c8sr0/ef43c15) (64-bit)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 406010005

=== NuGet ===


=== Xamarin.Profiler ===

Not Installed

=== Apple Developer Tools ===

Xcode 8.0 (11246)
Build 8A218a

=== Xamarin.Android ===

Version: (Xamarin Business)
Android SDK: Not found

=== Xamarin Android Player ===

Not Installed

=== Xamarin.iOS ===

Version: (Xamarin Business)
Hash: ad1cd42
Branch: cycle8-sr0-xi
Build date: 2016-10-03 15:18:44-0400

=== Xamarin.Mac ===

Not Installed

=== Build Information ===

Release ID: 601010015
Git revision: fa52f02641726146e2589ed86ec4097fbe101888
Build date: 2016-09-22 08:03:02-04
Xamarin addins: 75d65712af93d54dc39ae4c42b21dfa574859fd6
Build lane: monodevelop-lion-cycle8-sr0

=== Operating System ===

Mac OS X 10.11.6
Darwin Laures-MBP.lan 15.6.0 Darwin Kernel Version 15.6.0
    Mon Aug 29 20:21:34 PDT 2016
    root:xnu-3248.60.11~1/RELEASE_X86_64 x86_64
Comment 1 Rodrigo Kumpera 2016-10-13 22:37:15 UTC
Hi Richard,

Can you provide a test case that would enable us to reproduce your problem?
Comment 2 richard 2016-10-13 22:52:23 UTC
Hi there:

In terms of a code fragment - probably no. I could probably do a couple of things though:

1. I can get you configured with our Store Application to run on a device. If you simply login - you will crash the app with the right client customer DB loaded.
2. I believe I could also send you a copy of our App in the Simulator - same procedure - you open app - you will crash.

Not sure what would be easiest/possible. If there are other options - happy to do whatever to get this sorted out.
Comment 3 Vlad Brezae 2016-10-14 16:50:58 UTC
Hello Richard,

These type of bugs are pretty hard to debug and they normally require both having a debugger and recompilation of the runtime, which can be done pretty straightforward if we have the source code and we're compiling the app.

@zoltan Do you think we can work around this, to be able to debug, at least with the simulator ?
Comment 4 richard 2016-10-17 21:22:27 UTC
Hi Vlad:

We can get you a source code tree you can build. If you want to contact me on my email we can sort out the logistics of this.
Comment 5 Luis Aguilera 2016-10-27 13:56:38 UTC
fixed in https://github.com/mono/mono/pull/3833