Notice (2018-05-24): bugzilla.xamarin.com is now in
Please join us on
Visual Studio Developer Community and in the
Mono organizations on
GitHub to continue tracking issues. Bugzilla will remain
available for reference in read-only mode. We will continue to work
on open Bugzilla bugs, copy them to the new locations
as needed for follow-up, and add the new items under Related
Our sincere thanks to everyone who has contributed on this bug
tracker over the years. Thanks also for your understanding as we
make these adjustments and improvements for the future.
Please create a new report for Bug 33767 on
Developer Community or GitHub if you have new
information to add and do not yet see a matching new report.
If the latest results still closely match this report, you can use the
In special cases on GitHub you might also want the comments:
GitHub Markdown with public comments
Created attachment 12808 [details]
Logs with the error from LGE Nexus 5 and TCL 6014X
Sometimes the application crashes under heavy use of RAM with:
Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1)
Abort message: 'monodroid-glue.c:1033: gc_cleanup_after_java_collection: assertion "!sccs [i]->is_alive" failed'
In our case, it happens when user quickly switch to different fragments and activities many times.
The bug was found on the following devices: Lenovo S820 (API 19), TCL 6014X (API 18) (Alcatel One Touch), LGE Nexus 5 (API 22).
Most likely the problem persists also on other devices.
Part of the error is below:
[ F/libc ] monodroid-glue.c:1033: gc_cleanup_after_java_collection: assertion "!sccs [i]->is_alive" failed
[ E/mono-rt ] Stacktrace:
[ E/mono-rt ] at <unknown> <0xffffffff>
[ E/mono-rt ] at (wrapper managed-to-native) object.__icall_wrapper_mono_array_new_specific (intptr,int) <IL 0x0002a, 0xffffffff>
[ E/mono-rt ] at System.Collections.Generic.List`1.set_Capacity (int) <IL 0x0002b, 0x0010b>
[ E/mono-rt ] at System.Collections.Generic.List`1.EnsureCapacity (int) <IL 0x00048, 0x00177>
[ E/mono-rt ] at System.Collections.Generic.List`1.Add (T) <IL 0x0001c, 0x00083>
[ E/mono-rt ] at System.Collections.Generic.List`1..ctor (System.Collections.Generic.IEnumerable`1<T>) <IL 0x00086, 0x004cb>
[ E/mono-rt ] at System.Linq.Enumerable.ToList<TSource> (System.Collections.Generic.IEnumerable`1<TSource>) <IL 0x00007, 0x00093>
. . .
[ E/mono-rt ] at System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () <IL 0x00002, 0x00047>
[ E/mono-rt ] at System.Threading.ThreadPool.<UnsafeQueueCustomWorkItem>m__0 (object) <IL 0x00006, 0x000ff>
[ E/mono-rt ] at (wrapper runtime-invoke) <Module>.runtime_invoke_void__this___object (object,intptr,intptr,intptr) <IL 0x00062, 0xffffffff>
. . .
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
[ F/libc ] Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1), thread 20862 (.arview.fraisys)
[ I/DEBUG ] *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
[ I/DEBUG ] Build fingerprint: 'TCL/6014X/Miata_3G:4.3/JLS36C/vFCL-0:user/release-keys'
[ I/DEBUG ] Revision: '0'
[ I/DEBUG ] pid: 19916, tid: 20862, name: .arview.fraisys >>> com.arview.fraisys <<<
[ I/DEBUG ] signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr deadbaad
[ I/DEBUG ] Abort message: 'monodroid-glue.c:1033: gc_cleanup_after_java_collection: assertion "!sccs [i]->is_alive" failed'
## Steps to reproduce
According to the logs the error can caused by different sequences of function calls (in different logs - different sequence).
The common factor is the intensive use of memory and activation of garbage collection.
In our application, the easiest way to reproduce the bug quickly moving from screen to another screen many times.
@andreypavlov007: Would it be possible to get a repro project or a copy of your app and repro instructions?
What's the status on this? I am currently seeing this bug also and can reliably repro this using our application.
`is_alive` is set to `FALSE` by the bridge and expected to be set by the bridge callback (in monodroid) for objects to be kept alive. What seems to happen here is that, after linking up the strongly connected component Java objects and running a Java GC, we discover that within a single SCC only some objects are alive, which means that (barring memory corruption or other anything-goes bugs) either they weren't linked up correctly in the first place, or something interfered with the links in the mean time or, much less likely I think, the Java GC is buggy.
With Ludovic's suggestion, I tried using the Tarjan bridge.
Unfortunately, the app still crashes with the same reproduction steps. However, the logcat shows a possibly new issue:
[libc] Fatal signal 5 (SIGTRAP), code -6 in tid 27215 (OkHttp Dispatch)`
I attached the full logcat from this.
This is both a bug in the user code, and Xamarin.Android. The latter is at fault by failing to warn the user of errors in his code.
*** This bug has been marked as a duplicate of bug 35471 ***
I get very often crash with the only line of error after upgrade to Xamarin 4:
[libc] Fatal signal 5 (SIGTRAP), code -6 in tid 28636 (OkHttp Dispatch)
Absolutely have no idea what is the reproduce and why it happening.
To be honest, I don't think anything related to OkHttp processing at the moment of the crash (though I'm using it).
The device: Nexus 4
Let's break that message down:
This is the "tag" provided to android.util.Log.
> Fatal signal 5 (SIGTRAP)
What went wrong: SIGTRAP.
> code -6
No idea what the "code" is for.
> in tid 28636 (OkHttp Dispatch)
The ID (28636) and name ("OkHttp Dispatch") of the thread that generated the signal.
Putting it backwards, the "OkHttp Dispatch" thread triggered a SIGTRAP signal, which caused the process to abort.
What doesn't make sense is *why* it's triggering a SIGTRAP signal...
@Seifer: Does this happen if you run your app *without* debugging, or run a Release app?
@Jonathan, thank you for explanation and response.
I've noticed, that the crash does not happen on the Emulator (though it crashes a lot with weird stack-trace, but this is another story).
It feels, like the same Debug build launched *without* debugging does not crash on the device. But do crash when debugger connected.
Also, it usually crashes on the same screen (but not always).
In the attachment more info about the crash from actual logcat (for some reason, Xamarin Studio does not show this info)
Please, let me know if I can provide more information.
Created attachment 13972 [details]
Nexus 4 crash
According to the new log, the app crashed from another thread: (Filter)
But it crashes more often with (Ok HttpDispatch)
Reproducing now on latest Xamarin.Android Version: 220.127.116.11
[libc] Fatal signal 5 (???) at 0x00007a26 (code=-6), thread 31493 (OkHttp Dispatch)
Attached is new sample, which seems to reproduce the issue but does not seem to be a duplicate of bug 35471
Still got the problem.