feat: native signal handler strategy on Android #4676

jpnurmi · 2025-10-27T11:47:43Z

Opt-in, Android-only solution for:

Prevent Native/Cocoa SDKs from capturing errors that also get captured by .NET #3954

According to our newly introduced Android integration tests, getsentry/sentry-native#1392 works on android-arm64 and android-x64 in both Release and Debug configurations, but we'd like to validate the fix further in real-world conditions. To that end, we're making it opt-in initially so customers can try it on more devices, platforms, and configurations before considering it as the new default.

Note

Depends on:

github-actions · 2025-10-27T11:48:20Z

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against b64b284

codecov · 2025-10-27T12:03:59Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.87%. Comparing base (863ee6a) to head (b64b284).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4676      +/-   ##
==========================================
+ Coverage   73.85%   73.87%   +0.02%     
==========================================
  Files         483      494      +11     
  Lines       17578    17868     +290     
  Branches     3464     3509      +45     
==========================================
+ Hits        12982    13200     +218     
- Misses       3742     3808      +66     
- Partials      854      860       +6

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jpnurmi · 2025-11-04T11:24:38Z

@jamescrosswell This is marked as a draft because it's still waiting for dependencies, but we could already kick off the review process if you have time. :)

Do you have a preferred approach for exposing this as an opt-in API? The current proposal mirrors the sentry-native enum.

#if ANDROID
    options.Native.SignalHandlerStrategy = Sentry.Android.SignalHandlerStrategy.ChainAtStart;
#endif

With only two values, a simple boolean flag could also work for the time being, but I'm unsure if potential Android Tombstone support could change things in the future.

jpnurmi · 2026-01-26T11:38:56Z

Update: I'll get back to this after #4750 to make sure this works with .NET 10

…-handler-strategy

github-actions · 2026-02-07T09:16:21Z

Semver Impact of This PR

⚪ None (no version bump detected)

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Features ✨

feat: native signal handler strategy on Android by jpnurmi in #4676

_{🤖 This preview updates automatically when you update the PR.}

jpnurmi · 2026-02-09T13:35:08Z

While the signal handler strategy fixes the redundant SIGSEGV vs. NullReferenceException issue, the native exception test case breaks with .NET 10 on Android X86_64. 😢 All tests pass locally in an ARM64 Android emulator.

jpnurmi · 2026-02-09T15:51:51Z

.NET 10 on ARM64 and .NET 9.0 on both ARM64 and X86_64 behave as desired when sentry-native calls the runtime's signal handler. It returns to sentry-native which then captures the crash.

.NET 10 on X86_64, however, crashes trying to lock a destroyed mutex? No crash captured.

.NET 9.0 (Android ARM64 & X86_64) 👍

02-09 15:38:46.029  9141  9141 I DOTNET  :   Debug: Triggering a deliberate exception because SentrySdk.CauseCrash(CrashType.Native) was called
02-09 15:38:46.029  9141  9141 D app_process64:   Debug: Triggering a deliberate exception because SentrySdk.CauseCrash(CrashType.Native) was called
02-09 15:38:46.030  9141  9141 I sentry-native: entering signal handler
02-09 15:38:46.030  9141  9141 D sentry-native: defer to runtime signal handler at start
02-09 15:38:46.031  9141  9141 F libc    : Fatal signal 4 (SIGILL), code 0 (SI_USER) in tid 9141 (egrationtestapp), pid 9141 (egrationtestapp)
02-09 15:38:46.916  9176  9176 F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
02-09 15:38:46.916  9176  9176 F DEBUG   : Build fingerprint: 'google/sdk_gphone64_x86_64/emu64xa:16/BE2A.250530.026.F3/13894323:userdebug/dev-keys'
02-09 15:38:46.916  9176  9176 F DEBUG   : Revision: '0'
02-09 15:38:46.916  9176  9176 F DEBUG   : ABI: 'x86_64'
02-09 15:38:46.916  9176  9176 F DEBUG   : Timestamp: 2026-02-09 15:38:46.136533669+0100
02-09 15:38:46.916  9176  9176 F DEBUG   : Process uptime: 2s
02-09 15:38:46.916  9176  9176 F DEBUG   : Cmdline: io.sentry.dotnet.maui.device.integrationtestapp
02-09 15:38:46.916  9176  9176 F DEBUG   : pid: 9141, tid: 9141, name: egrationtestapp  >>> io.sentry.dotnet.maui.device.integrationtestapp <<<
02-09 15:38:46.916  9176  9176 F DEBUG   : uid: 10235
02-09 15:38:46.916  9176  9176 F DEBUG   : signal 4 (SIGILL), code 0 (SI_USER), fault addr --------
02-09 15:38:46.916  9176  9176 F DEBUG   :     rax 0000000000000000  rbx 00006fff13d88298  rcx 000070002be8ac70  rdx 0000000000000200
02-09 15:38:46.916  9176  9176 F DEBUG   :     r8  0000000000000002  r9  00007fff348293f0  r10 0000000000000005  r11 00006ffe94ecf9d0
02-09 15:38:46.916  9176  9176 F DEBUG   :     r12 000070008c9f9fb0  r13 000070002be8ac80  r14 00006ffe8a9f35f0  r15 000070011be91d80
02-09 15:38:46.916  9176  9176 F DEBUG   :     rdi 000070011be91d80  rsi 0000000000000006
02-09 15:38:46.916  9176  9176 F DEBUG   :     rbp 00006fff13d88298  rsp 00007fff348293c8  rip 00006ffe8a9f35f0
02-09 15:38:46.916  9176  9176 F DEBUG   : 2 total frames
02-09 15:38:46.916  9176  9176 F DEBUG   : backtrace:
02-09 15:38:46.916  9176  9176 F DEBUG   :       #00 pc 00000000000005f0  /data/app/~~Z3VBUbKXonuWeLlN4W2eXQ==/io.sentry.dotnet.maui.device.integrationtestapp-gqdBX9FklKvyqOkUvbN8Zw==/lib/x86_64/libsentrysupplemental.so (crash+0) (BuildId: c2d6e5ae745143957e682d1b4fd73eac1d41a339)
02-09 15:38:46.916  9176  9176 F DEBUG   :       #01 pc 00000000000f4cc8  <anonymous:4a5c6000>
02-09 15:38:46.931  9141  9141 D sentry-native: return from runtime signal handler, we handle the signal
02-09 15:38:46.937  9141  9141 D sentry-native: captured backtrace from ucontext with 2 frames
02-09 15:38:46.937  9141  9141 D sentry-native: captured backtrace with 2 frames
02-09 15:38:46.938  9141  9141 D sentry-native: merging global scope into event
02-09 15:38:46.938  9141  9141 D sentry-native: trying to read modules from /proc/self/maps
02-09 15:38:46.975  9141  9141 D sentry-native: read 443 modules from /proc/self/maps
02-09 15:38:46.975  9141  9141 D sentry-native: sending envelope
02-09 15:38:46.976  9141  9141 I sentry-native: crash has been captured

NET 10.0 (Android ARM64) 👍

02-09 16:44:27.396  8471  8471 I DOTNET  :   Debug: Triggering a deliberate exception because SentrySdk.CauseCrash(CrashType.Native) was called
02-09 16:44:27.396  8471  8471 D app_process64:   Debug: Triggering a deliberate exception because SentrySdk.CauseCrash(CrashType.Native) was called
02-09 16:44:27.398  8471  8471 I sentry-native: entering signal handler
02-09 16:44:27.398  8471  8471 D sentry-native: defer to runtime signal handler at start
02-09 16:44:27.398  8471  8471 F libc    : Fatal signal 5 (SIGTRAP), code 1 (TRAP_BRKPT), fault addr 0x79af81d5a8 in tid 8471 (egrationtestapp), pid 8471 (egrationtestapp)
02-09 16:44:27.875  8508  8508 F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
02-09 16:44:27.875  8508  8508 F DEBUG   : Build fingerprint: 'google/sdk_gphone64_arm64/emu64a:16/BE2A.250530.026.D1/13818094:user/release-keys'
02-09 16:44:27.875  8508  8508 F DEBUG   : Revision: '0'
02-09 16:44:27.875  8508  8508 F DEBUG   : ABI: 'arm64'
02-09 16:44:27.875  8508  8508 F DEBUG   : Timestamp: 2026-02-09 16:44:27.434533683+0100
02-09 16:44:27.875  8508  8508 F DEBUG   : Process uptime: 2s
02-09 16:44:27.875  8508  8508 F DEBUG   : Cmdline: io.sentry.dotnet.maui.device.integrationtestapp
02-09 16:44:27.875  8508  8508 F DEBUG   : pid: 8471, tid: 8471, name: egrationtestapp  >>> io.sentry.dotnet.maui.device.integrationtestapp <<<
02-09 16:44:27.875  8508  8508 F DEBUG   : uid: 10339
02-09 16:44:27.875  8508  8508 F DEBUG   : tagged_addr_ctrl: 0000000000000001 (PR_TAGGED_ADDR_ENABLE)
02-09 16:44:27.875  8508  8508 F DEBUG   : pac_enabled_keys: 000000000000000f (PR_PAC_APIAKEY, PR_PAC_APIBKEY, PR_PAC_APDAKEY, PR_PAC_APDBKEY)
02-09 16:44:27.875  8508  8508 F DEBUG   : signal 5 (SIGTRAP), code 1 (TRAP_BRKPT), fault addr 0x00000079af81d5a8
02-09 16:44:27.875  8508  8508 F DEBUG   :     x0  00000079af81d5a8  x1  0000000000000006  x2  b400007bc1c84138  x3  b400007c51c1d888
02-09 16:44:27.875  8508  8508 F DEBUG   :     x4  0000007fdebc1238  x5  b400007c51c1d8e0  x6  6f732e6c61746e65  x7  b400007b91d58798
02-09 16:44:27.875  8508  8508 F DEBUG   :     x8  0000000000000200  x9  0000000000000002  x10 0000000000000001  x11 00000000b74f8fcb
02-09 16:44:27.875  8508  8508 F DEBUG   :     x12 0000000000019002  x13 b6f2fcf39918a7a7  x14 0000000000000008  x15 b400007b020651e8
02-09 16:44:27.875  8508  8508 F DEBUG   :     x16 0000000000000001  x17 0000007d7a904fd0  x18 0000007da9ef4000  x19 0000000000000001
02-09 16:44:27.875  8508  8508 F DEBUG   :     x20 0000007fdebc1400  x21 0000007ada32c298  x22 0000007ada32c298  x23 b400007b0276a2f8
02-09 16:44:27.875  8508  8508 F DEBUG   :     x24 b400007c91c07650  x25 0000007a49a5b590  x26 b400007bc1c84120  x27 0000000000000000
02-09 16:44:27.875  8508  8508 F DEBUG   :     x28 0000007fdebc1860  x29 0000007fdebc1220
02-09 16:44:27.875  8508  8508 F DEBUG   :     lr  0000007d99c724dc  sp  0000007fdebc1220  pc  00000079af81d5a8  pst 0000000080001000
02-09 16:44:27.875  8508  8508 F DEBUG   : 2 total frames
02-09 16:44:27.875  8508  8508 F DEBUG   : backtrace:
02-09 16:44:27.875  8508  8508 F DEBUG   :       #00 pc 00000000000005a8  /data/app/~~s1hgF6ZtWJQ9vnEajeatvA==/io.sentry.dotnet.maui.device.integrationtestapp-uNphE0qc7n7bR5e8MYGTxg==/lib/arm64/libsentrysupplemental.so (crash+0) (BuildId: f20ec64b4897db5a4517ffb4f61067017ceb3b87)
02-09 16:44:27.875  8508  8508 F DEBUG   :       #01 pc 000000000000b4d8  <anonymous:7d99c67000>
02-09 16:44:27.887  8471  8471 D sentry-native: return from runtime signal handler, we handle the signal
02-09 16:44:27.898  8471  8471 D sentry-native: captured backtrace from ucontext with 2 frames
02-09 16:44:27.898  8471  8471 D sentry-native: captured backtrace with 2 frames
02-09 16:44:27.898  8471  8471 D sentry-native: merging global scope into event
02-09 16:44:27.898  8471  8471 D sentry-native: trying to read modules from /proc/self/maps
02-09 16:44:27.944  8471  8471 D sentry-native: read 443 modules from /proc/self/maps
02-09 16:44:27.945  8471  8471 D sentry-native: sending envelope
02-09 16:44:27.945  8471  8471 I sentry-native: crash has been captured

NET 10.0 (Android X86_64) 👎

02-09 15:41:14.428  9380  9380 I DOTNET  :   Debug: Triggering a deliberate exception because SentrySdk.CauseCrash(CrashType.Native) was called
02-09 15:41:14.428  9380  9380 D app_process64:   Debug: Triggering a deliberate exception because SentrySdk.CauseCrash(CrashType.Native) was called
02-09 15:41:14.429  9380  9380 I sentry-native: entering signal handler
02-09 15:41:14.429  9380  9380 D sentry-native: defer to runtime signal handler at start
02-09 15:41:14.429  9380  9411 F libc    : FORTIFY: pthread_mutex_lock called on a destroyed mutex (0x7001ba602c38)
02-09 15:41:14.429  9380  9410 F libc    : FORTIFY: pthread_mutex_lock called on a destroyed mutex (0x7001ba602c38)
02-09 15:41:14.458   711  2169 I ActivityManager: Process io.sentry.dotnet.maui.device.integrationtestapp (pid 9380) has died: fg  TOP
02-09 15:41:14.459   485   485 I Zygote  : Process 9380 exited due to signal 6 (Aborted)

jpnurmi · 2026-02-10T12:38:01Z

Claude confidently claims the issue was fixed by:

[Mono]: Fix stackwalk callbacks calling mono_jit_info_get_method in async signal safe mode. dotnet/runtime#123346

The fix was backported to release/10.0. We can give it a try later with the next .NET 10 release.

Investigation: .NET 10 x86_64 native crash test failure

Traced the root cause via strace on the Android emulator.

What happens

When sentry-native defers to Mono's signal handler (CHAIN_AT_START), Mono's mono_handle_native_crash walks the managed stack. On .NET 10, this walk uses the MONO_UNWIND_SIGNAL_SAFE flag (added in d34ef7e), which causes AOT method JIT info to be loaded in async-safe mode with ji->async = TRUE. The stack walk callback print_stack_frame_signal_safe was not updated to check !ji->async before calling mono_jit_info_get_method(), which hits:

Assertion at jit-info.c:918, condition !ji->async not met

The assertion triggers abort(), and since mono_handle_native_crash already reset SIGABRT to SIG_DFL, the process is killed immediately — before control returns to sentry-native.

Fix

Already merged upstream:

[Mono]: Fix stackwalk callbacks calling mono_jit_info_get_method in async signal safe mode. dotnet/runtime#123346 (f49873c) — adds !ji->async check to print_stack_frame_signal_safe and mono_find_jit_info
Backported to release/10.0 as [release/10.0] [Mono]: Fix stackwalk callbacks calling mono_jit_info_get_method in async signal safe mode. dotnet/runtime#123792 (cdc557a) on Feb 6, 2026
Related issue: Critical SIGABRT crash in .NET 10 Android (ARM64) – Assertion jit-info.c:918 (!ji->async) dotnet/runtime#122797

This was referenced Oct 27, 2025

fix: AOT interop with managed .NET runtimes getsentry/sentry-native#1392

Merged

Prevent Native/Cocoa SDKs from capturing errors that also get captured by .NET #3954

Open

jpnurmi mentioned this pull request Nov 4, 2025

chore(deps): update Native SDK to v0.12.1 getsentry/sentry-java#4859

Merged

Base automatically changed from version6 to main November 14, 2025 02:30

jpnurmi force-pushed the feat/android-signal-handler-strategy branch from af57caa to 4486918 Compare November 20, 2025 10:31

jpnurmi force-pushed the feat/android-signal-handler-strategy branch from 4486918 to 7a489eb Compare January 2, 2026 08:02

jpnurmi added 2 commits January 2, 2026 15:55

feat: allow configuring native signal handler strategy on Android

e2d1003

Update CHANGELOG.md

543b3e3

jpnurmi force-pushed the feat/android-signal-handler-strategy branch from 7a489eb to 543b3e3 Compare January 2, 2026 14:57

Merge remote-tracking branch 'upstream/main' into feat/android-signal…

e126a63

…-handler-strategy

jpnurmi added the Blocked label Feb 10, 2026

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