NETWORK_CAPABILITIES_CHANGED and BATTERY_CHANGED events on Android (with Maui) causing SIGSEGV Segfault

[drewrobey]

Package

Sentry

.NET Flavor

.NET

.NET Version

9.0

OS

Android

SDK Version

4.13.0

Self-Hosted Sentry Version

No response

Steps to Reproduce

1. Create .Net MAUI application in Visual Studio.
2. Install Sentry.Maui from Nuget and setup.
3. Build a Release version of the Android app and install on mobile phone.
4. The app will crash within first 30 seconds of startup.

Expected Result

App should not crash.

Actual Result

As per Keren from Sentry's request I've created this issue, he's my original support message:

I'm using Sentry with .Net Maui, and I think I may have discovered a bug.

We've been receiving SEGFAULT runtime errors - apps crashing after maybe 20 seconds of startup, triggered by NETWORK_CAPABILITIES_CHANGED and BATTERY_CHANGED events. This problem has been reported by someone else to the Maui team via Github, and I've been helping to investigate the issue dotnet/maui#25446

I've discovered that the common denominator with all users having these problems is that they're using Sentry.Maui

When we remove Sentry from our builds the crashes stop. When we add Sentry back in, and remove AOT and trimming, the crashes stop. It looks like the Maui compilation linker is trimming certain methods from the Sentry plugin, which is causing the crashes, as these methods are clearly being called somewhere, possibly being called via Reflection or the like.

Perhaps it's possible to have Sentry's classes marked with directives to prevent trimming, so that they're preserved in-full during compilation?

[bitsandfoxes]

Thanks for reaching out!
I'm not too familiar with the trimming options but I was under the impression that we add the assembly as root for the trimmer? But I can't find where this happens anymore. Maybe @jamescrosswell knows?

[drewrobey]

@bitsandfoxes I'm in the UK so I'm not at my desk right now, but tomorrow I'll try and attach some screenshots of the AOT settings to illustrate what I mean a bit better.

[bruno-garcia]

Just a thought, not sure it'll help but does this happen on the latest preview release of the SDK? version 5

[jamescrosswell]

Hi @drewrobey, if you're using .NET 9 then you'll want/need to use Sentry version 5.x. Version 4.x wasn't built or tested with .NET 9.

Version 5.0.0 isn't yet available. We're hoping to have an early beta available in the couple of weeks. One of the main things that we have to do before making that release is enable the new AOT analyzers for MAUI apps and work through any/all warnings that those produce... so working through issues like this, basically.

It'd be great to get some help testing that from people who are already looking to move to .NET 9.

[drewrobey]

@jamescrosswell I've only upgraded to .net 9 in this last week, and before that the same crashes were occurring on .net 8

[drewrobey]

Further to my comment from last night, here's a screenshot of the Visual Studio build settings that I'm referring to, namely the AOT and trimming settings - the nuclear option I've found prevents the crashes is to turn off AOT entirely.

[bruno-garcia]

This helps narrow down. Thanks

[drewrobey]

The email bot is saying it'll close the ticket if I don't respond, so here's a response to make sure that doesn't happen...

[bruno-garcia]

are you sure it was on this ticket? we won't let it close, don't worry.

[drewrobey]

@bruno-garcia Yep, it was this ticket: it's the only Sentry ticket I've opened.

[drewrobey]

@bruno-garcia Just received another one of the automated emails from sentry.io, the content says:

Hope all is well with you! Just dropping in to say we haven't heard back from you about your ticket. We still want to help if you're stuck.

Since it's been a while, we'll be closing the ticket for now. But hey, don't worry! If there's anything more you need or if you want to reopen the ticket, just shoot us a message anytime.

Would it auto-close the ticket if there's no new info?

[bruno-garcia]

@bruno-garcia Just received another one of the automated emails from sentry.io, the content says:

Hope all is well with you! Just dropping in to say we haven't heard back from you about your ticket. We still want to help if you're stuck.

Since it's been a while, we'll be closing the ticket for now. But hey, don't worry! If there's anything more you need or if you want to reopen the ticket, just shoot us a message anytime.

Would it auto-close the ticket if there's no new info?

it will not. It would take a long time and we would see this message on the ticket. The bot writes on GitHub, that email doesn't come from Sentry it's just a github notification via email. Unless this is an old email, or about another issue, I'm not sure why you would receive it.

[Mittchel]

We are experiencing the same thing on a lot of our apps at the moment. Today one of our apps actually got rejected.

Has anyone tested whether this issue occurs on the 5.0.0 alpha package?

[jamescrosswell]

Has anyone tested whether this issue occurs on the 5.0.0 alpha package?

I haven't had time to look at this issue (or been able to reproduce it yet).

I've kind of been working on it indirectly - This PR ensures Sentry.Maui is trim compatible... once that's merged, we could put together another pre-release to see if it has any impact on this issue.

There's also one other change in the version 5.0.0 branch that relates to issues reading the network status, so that could potentially be related. Again, we could test that in the next pre-release.

Apologies for the wait on this - we're a bit short handed on the .NET SDK at the moment.

[jamescrosswell]

Further to my comment from last night, here's a screenshot of the Visual Studio build settings that I'm referring to, namely the AOT and trimming settings - the nuclear option I've found prevents the crashes is to turn off AOT entirely.

@drewrobey from what I can tell, AOT isn't yet supported on Android:

• Cross-OS native compilation is not supported. dotnet/runtime#109284 (comment)

The tracking issues there seem to have a .NET 10.0 milestone:

• Fix known issues with NativeAOT dotnet/java-interop#1192
• Fix known issues with NativeAOT dotnet/android#8724
• NativeAOT status for Android dotnet/runtime#106748

In our own samples, we only enable this for ios and maccatalyst targets:

sentry-dotnet/samples/Sentry.Samples.Maui/Sentry.Samples.Maui.csproj

Lines 48 to 50 in a421af5

	<PropertyGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios' or $([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'maccatalyst'">
	<PublishAot>true</PublishAot>
	</PropertyGroup>

[drewrobey]

@jamescrosswell That's interesting.

Doing some further reading it turns out full AOT for Android does indeed not exist, but partial AOT does, which would explain why the AOT build option has been in there for Android since the Xamarin days:

Partial AOT for Startup Optimization:

    The AOT option in Visual Studio applies to startup-critical paths rather than the entire application.
    This can improve application launch times and runtime performance by precompiling certain code segments into native machine code.

Integration from Xamarin.Android:

    .NET MAUI inherits features from Xamarin.Android, which supports partial AOT for performance tuning.
    The AOT option targets specific assemblies or methods to reduce JIT overhead.

FYI there have been a couple of Maui framework Nuget updates in the last couple of days, that I'm currently experimenting with - let me see if these have any effect on this bug, as there's a lot of changes happening all of a sudden, and I need to isolate some variables to ensure I'm not sending you on a wild goose chase.