invalid pthread_t 0x<sanitized> passed to pthread_kill coming from startProfiling

What React Native libraries do you use?

Hermes, RN New Architecture, React Navigation, Expo Application Services (EAS), Expo (mobile only)

Are you using sentry.io or on-premise?

sentry.io (SaS)

@sentry/react-native SDK Version

7.7.0

How does your development environment look like?

We're in a pnpm monorepo with Expo so I don't think it'll get much useful info. Here's what I get from that:

⚠️ react-native depends on @react-native-community/cli for cli commands. To fix update your package.json to include:


  "devDependencies": {
    "@react-native-community/cli": "latest",
  }

Sentry.init()

Sentry.init({
    environment: <we get this dynamically with a function call>
    release: <we get this dynamically with a function call>,
    dist,
    dsn: sentryEnabled ? 'our-dsn' : undefined,

    // Enable this only if you're testing Sentry changes in development
    debug: false,
    tracesSampleRate: 0.1,
    profilesSampleRate: 0.1,

    replaysOnErrorSampleRate: enableSessionReplay ? 0.05 : 0,
    replaysSessionSampleRate: 0,

    integrations: [
      navigationInstrumentation, // Capture navigation breadcrumbs & performance spans
      sentryMobileReplayIntegration({
        maskAllText: true,
        maskAllImages: false,
        maskAllVectors: false,
      }),
    ],
    initialScope: {
      tags: (() => {
        const baseTags: Record<string, string | undefined> = {...someTagsHere};
        return baseTags;
      })(),
    },
});

Steps to Reproduce

I did my best to reproduce this, but it seems to be an intermittent issue in production. I think the root cause may be threading issues, which is hard to artificially force.

Here's what I know:

Google Play Console is reporting a crash with this error:

invalid pthread_t 0x<sanitized> passed to pthread_kill

Here's the stack trace in Google Play:

*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
pid: 0, tid: 5131 >>> com.my.app <<<

backtrace:
  #00  pc 0x000000000007123c  /apex/com.android.runtime/lib64/bionic/libc.so (abort+160)
  #01  pc 0x0000000000082c28  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_internal_find(long, char const*)+196)
  #02  pc 0x0000000000082b44  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_internal_gettid(long, char const*)+12)
  #03  pc 0x0000000000083948  /apex/com.android.runtime/lib64/bionic/libc.so (pthread_kill+52)
  #04  pc 0x00000000001105e0  /data/app/~~GVAFjiv3MRHi6wN_jyFNGQ==/com.my.app-dfsyqHFTuzXmYnuve2e92g==/split_config.arm64_v8a.apk!libhermes.so (BuildId: b06c77a49801680608345e3c05bd59aba90e9f19)
  #05  pc 0x0000000000110a60  /data/app/~~GVAFjiv3MRHi6wN_jyFNGQ==/com.my.app-dfsyqHFTuzXmYnuve2e92g==/split_config.arm64_v8a.apk!libhermes.so (BuildId: b06c77a49801680608345e3c05bd59aba90e9f19)
  #06  pc 0x000000000011095c  /data/app/~~GVAFjiv3MRHi6wN_jyFNGQ==/com.my.app-dfsyqHFTuzXmYnuve2e92g==/split_config.arm64_v8a.apk!libhermes.so (BuildId: b06c77a49801680608345e3c05bd59aba90e9f19)
  #07  pc 0x0000000000110d78  /data/app/~~GVAFjiv3MRHi6wN_jyFNGQ==/com.my.app-dfsyqHFTuzXmYnuve2e92g==/split_config.arm64_v8a.apk!libhermes.so (BuildId: b06c77a49801680608345e3c05bd59aba90e9f19)
  #08  pc 0x0000000000111480  /data/app/~~GVAFjiv3MRHi6wN_jyFNGQ==/com.my.app-dfsyqHFTuzXmYnuve2e92g==/split_config.arm64_v8a.apk!libhermes.so (BuildId: b06c77a49801680608345e3c05bd59aba90e9f19)
  #09  pc 0x0000000000082600  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_start(void*)+184)
  #10  pc 0x0000000000074a58  /apex/com.android.runtime/lib64/bionic/libc.so (__start_thread+68)

And here's that same trace symbolicated with Hermes:

*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
pid: 0, tid: 15474 >>> com.my.app <<<

backtrace:
  #00  pc 0x000000000007137c  /apex/com.android.runtime/lib64/bionic/libc.so (abort+160)
  #01  pc 0x0000000000082d68  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_internal_find(long, char const*)+196)
  #02  pc 0x0000000000082c84  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_internal_gettid(long, char const*)+12)
  #03  pc 0x0000000000083a88  /apex/com.android.runtime/lib64/bionic/libc.so (pthread_kill+52)
  #04  pc 0x00000000001105e0  libhermes.so
       hermes::vm::sampling_profiler::Sampler::platformSuspendVMAndWalkStack(hermes::vm::SamplingProfiler*)
       SamplingProfilerPosix.cpp:321
  #05  pc 0x0000000000110a60  libhermes.so
       hermes::vm::sampling_profiler::Sampler::sampleStack(hermes::vm::SamplingProfiler*)
       SamplingProfilerSampler.cpp:99
  #06  pc 0x000000000011095c  libhermes.so
       hermes::vm::sampling_profiler::Sampler::sampleStacks()
       SamplingProfilerSampler.cpp:62
  #07  pc 0x0000000000110d78  libhermes.so
       hermes::vm::sampling_profiler::Sampler::timerLoop(double)
       SamplingProfilerSampler.cpp:162
  #08  pc 0x0000000000111480  libhermes.so
       std::__ndk1::__thread_proxy<...>(void*)
       __thread/thread.h:199
  #09  pc 0x0000000000082740  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_start(void*)+184)
  #10  pc 0x0000000000074b98  /apex/com.android.runtime/lib64/bionic/libc.so (__start_thread+68)

---
Analysis: Crash in Hermes Sampling Profiler

The sampling profiler's background thread called pthread_kill() to send a signal 
to a JavaScript thread for stack sampling, but the target thread no longer exists 
(or has an invalid thread ID). This caused __pthread_internal_find() to fail and 
call abort().

This is a race condition: the profiler's timer loop tried to sample a thread that 
was terminated between when the profiler registered it and when the sample was attempted.

Hermes version: 0.79.6 (React Native 0.79.6)
Build ID: b06c77a49801680608345e3c05bd59aba90e9f19

I brought this up with the Hermes maintainers. This issue can happen when something calls the Hermes profiler, and if the relevant thread can't be addressed. A long time ago, React Native Reanimated had this issue in some instances. And I found that @sentry/react-native seems to be calling methods that would trigger this profiling as well.

startProfiling calls HermesSamplingProfiler.enable, which in turn calls hermesAPI->enableSamplingProfiler():

public WritableMap startProfiling(boolean platformProfilers) {
    final WritableMap result = new WritableNativeMap();
    if (androidProfiler == null && platformProfilers) {
      initializeAndroidProfiler();
    }

    try {
      HermesSamplingProfiler.enable();
      if (androidProfiler != null) {
        androidProfiler.start();
      }

      result.putBoolean("started", true);
    } catch (Throwable e) { // NOPMD - We don't want to crash in any case
      result.putBoolean("started", false);
      result.putString("error", e.toString());
    }
    return result;
  }

sentry-react-native/packages/core/android/src/main/java/io/sentry/react/RNSentryModuleImpl.java

Lines 946 to 964 in 0dd606f

    
           public WritableMap startProfiling(boolean platformProfilers) { 
        
             final WritableMap result = new WritableNativeMap(); 
        
             if (androidProfiler == null && platformProfilers) { 
        
               initializeAndroidProfiler(); 
        
             } 
        
             try { 
        
               HermesSamplingProfiler.enable(); 
        
               if (androidProfiler != null) { 
        
                 androidProfiler.start(); 
        
               } 
        
               result.putBoolean("started", true); 
        
             } catch (Throwable e) { // NOPMD - We don't want to crash in any case 
        
               result.putBoolean("started", false); 
        
               result.putString("error", e.toString()); 
        
             } 
        
             return result; 
        
           }

(I found this code is the same 7.7.0 tag as well)

Which calls:

void HermesSamplingProfiler::enable(jni::alias_ref<jclass> /*unused*/) {
  auto* hermesAPI =
      castInterface<hermes::IHermesRootAPI>(hermes::makeHermesRootAPI());
  hermesAPI->enableSamplingProfiler();
}

The Hermes team considers this to be atypical.

Again, I don't have a formal reproducer (I believe we'd need to line up exactly the right conditions: get traces started on threads that become unaddressable - I can't figure out the code needed to reproduce). But I'm hoping this is enough information for you all to track it down. If you've got ideas of what might reproduce this, that would be helpful to me (and I'd be happy to put together a clearer reproduction).

I'm hoping the solution is as simple as adding some kind of error handling in your startProfiling method so that if we hit this pthread error, the app does not crash. Right now we seem to be getting SIGABRT errors. If we can just catch and handle those, I think that would fix my issue. Again, without a reproducer I can't quite reason out what needs to change, but I'm hoping y'all would have a good idea.

Expected Result

App should never crash when Sentry profiling is run. Right now this happens fairly infrequently (about 1-3% of users, maybe?) - but I think this should be 0%.

Actual Result

Seeing crashes in Google Play Console.

RN-420

@coolsoftwaretyler

Thank you for reporting and the detailed issue description @coolsoftwaretyler 🙇
We will investigate this and iterate back.

@coolsoftwaretyler

Thank you for your patience on this @coolsoftwaretyler. Just a heads up that we haven't figured a way to reproduced this but we are still looking at the issue. You detailed investigation is really helpful 🙇
Please also let us know if you notice the crash again after disabling the feature.

Thanks, all! I'll have more data from production soon and will follow up with what I observe.

Hey folks, I have roughly 3 days worth of data across the same user base. In the app version with profilesSampleRate set to 0, we have not seen any more of these crashes reported to Google Play.

I have a reminder set to follow up on the it next week, but early evidence continues to point at profiling as the source here.

@coolsoftwaretyler

Hi @coolsoftwaretyler @antonis - do we have any updates on this? thanks in advance!

@ryanunirabaga

Thank you for the ping @ryanunirabaga 🙇 We are working on mitigating the issue with #6035 and exploring a fix on the Hermes side. We do not have a clear ETA yet.

fix(android): Stop Hermes profiler on React instance teardown (#6035)

Shipped a mitigation in 8.9.1 and working on a Hermes side fix

Fix sampling profiler race when registered thread exits

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invalid pthread_t 0x<sanitized> passed to pthread_kill coming from startProfiling #5441

What React Native libraries do you use?

Are you using sentry.io or on-premise?

@sentry/react-native SDK Version

How does your development environment look like?

Sentry.init()

Steps to Reproduce

Expected Result

Actual Result

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	public WritableMap startProfiling(boolean platformProfilers) {
	final WritableMap result = new WritableNativeMap();
	if (androidProfiler == null && platformProfilers) {
	initializeAndroidProfiler();
	}

	try {
	HermesSamplingProfiler.enable();
	if (androidProfiler != null) {
	androidProfiler.start();
	}

	result.putBoolean("started", true);
	} catch (Throwable e) { // NOPMD - We don't want to crash in any case
	result.putBoolean("started", false);
	result.putString("error", e.toString());
	}
	return result;
	}

invalid pthread_t 0x<sanitized> passed to pthread_kill coming from startProfiling #5441

Description

What React Native libraries do you use?

Are you using sentry.io or on-premise?

@sentry/react-native SDK Version

How does your development environment look like?

Sentry.init()

Steps to Reproduce

Expected Result

Actual Result

Activity

linear commented on Dec 4, 2025

antonis commented on Dec 5, 2025

antonis commented on Dec 10, 2025

coolsoftwaretyler commented on Dec 10, 2025

coolsoftwaretyler commented on Dec 11, 2025

34 remaining items

ryanunirabaga commented on Apr 23, 2026

antonis commented on Apr 23, 2026

antonis commented on Apr 24, 2026

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