Fantom's tester prints no stack when it crashes: it installs no failure signal handler, and its glog config.h compiles the handler and the symbolizer out

Start from private/react-native-fantom/tester/src/main.cpp and packages/react-native/ReactAndroid/src/main/jni/third-party/glog/config.h where the issue supplies exact diffs. Apply the three hunks, then rebuild with yarn workspace @react-native/fantom build and ./gradlew :private:react-native-fantom:buildFantomTester --rerun. Done when a SIGSEGV crash prints named frames such as faultOnNullWrite().

Description

When Fantom's tester crashes in native code, the runner reports Command failed (status code: (empty), signal: SIGSEGV) with empty stdout and stderr, so nothing says where it died.

The tester's main initializes glog but never calls google::InstallFailureSignalHandler() (main.cpp L20-L24). Adding the call alone changes nothing: the tester builds glog with the Android config.h (config.h), which never defines HAVE_SIGACTION, and glog 0.3.5's InstallFailureSignalHandler is empty without it (signalhandler.cc L354-L366).

With HAVE_SIGACTION defined, the handler prints the signal, but every frame reads (unknown). The same config.h ends with #undef OS_LINUX (L178-L181). glog's utilities.h defines OS_LINUX from __linux__ (L42), then includes config.h (L81), then defines HAVE_SYMBOLIZE only #if defined(__ELF__) && defined(OS_LINUX) (L125-L126), so Symbolize compiles to its stub on a Linux host.

Defining HAVE_SIGACTION and keeping OS_LINUX (and the syscall headers) when __ANDROID__ is not defined, plus the one call in main, gives a crash report naming each frame's function. The patches in the reproducer show each step:

--- a/private/react-native-fantom/tester/src/main.cpp
+++ b/private/react-native-fantom/tester/src/main.cpp
@@ -21,6 +21,7 @@
   google::InitGoogleLogging("react-native-fantom");
   FLAGS_logtostderr = true;
   FLAGS_minloglevel = AppSettings::minLogLevel;
+  google::InstallFailureSignalHandler();
 }
 
 static void setUpFeatureFlags() {
--- a/packages/react-native/ReactAndroid/src/main/jni/third-party/glog/config.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/third-party/glog/config.h
@@ -64,6 +64,10 @@
 /* Define if you have the `sigaltstack' function */
 #define HAVE_SIGALTSTACK 1
 
+#if !defined(__ANDROID__)
+#define HAVE_SIGACTION 1
+#endif
+
 /* Define to 1 if you have the <stdint.h> header file. */
 #define HAVE_STDINT_H 1
 
@@ -176,7 +180,9 @@
 
 
 /* TODO(vjn/dreiss): revisit these when use the android-21 (or newer) NDK platform. */
+#if defined(__ANDROID__)
 #undef HAVE_SYSCALL_H
 #undef HAVE_SYS_SYSCALL_H
 #undef OS_LINUX
+#endif
 #undef OS_MACOSX

Under AddressSanitizer or ThreadSanitizer the sanitizer's own report already prints the stack, so the call could be left out of those builds.

Steps to reproduce

1. git clone https://github.com/YevheniiKotyrlo/react-native-fantom-reproducer && cd react-native-fantom-reproducer

2. ./fantom/reproduce.sh crash-prints-no-stack (needs Docker). It clones react/react-native at main and builds Fantom's tester as CI does, then:

   1. applies fantom/null-write-in-clear-all-images.patch, which makes NativeFantom::clearAllImages write through a null pointer in a function named faultOnNullWrite, and copies fantom/NativeCrash-itest.js, a test that calls NativeFantom.clearAllImages(), into private/react-native-fantom/src/__tests__/;
   2. runs yarn fantom private/react-native-fantom/src/__tests__/NativeCrash-itest.js on that tester;
   3. applies fantom/install-failure-signal-handler.patch (the main.cpp hunk above), rebuilds and runs the test again;
   4. applies fantom/glog-config-sigaction.patch (HAVE_SIGACTION), rebuilds and runs it again;
   5. applies fantom/glog-config-keep-os-linux.patch (OS_LINUX kept), rebuilds and runs it once more.

   Each rebuild runs ./gradlew :private:react-native-fantom:buildFantomTester --rerun after yarn workspace @react-native/fantom build, since Gradle calls the tester up to date after a change to glog's config.h.

Expected: the crash's report names SIGSEGV and the crashing frame, faultOnNullWrite().

Actual: on main at f1f1474, steps 2 and 3 print stderr: (empty); step 4 prints the signal and 24 frames, each (unknown); only step 5 names faultOnNullWrite(), NativeFantom::clearAllImages() and the frames up to main.

React Native Version

0.88.0 (reproduced on main at f1f1474)

Affected Platforms

Build - Linux

Output of npx @react-native-community/cli info

System:
  OS: Linux 6.18 Ubuntu 22.04.5 LTS 22.04.5 LTS (Jammy Jellyfish)
  CPU: (24) x64 AMD Ryzen 9 9950X3D 16-Core Processor
  Memory: 121.74 GB / 125.63 GB
  Shell:
    version: 5.1.16
    path: /bin/bash
Binaries:
  Node:
    version: 22.14.0
    path: /usr/local/bin/node
  Yarn:
    version: 1.22.22
    path: /usr/local/bin/yarn
  npm:
    version: 10.9.2
    path: /usr/local/bin/npm
  Watchman: Not Found
SDKs:
  Android SDK:
    API Levels:
      - "37"
    Build Tools:
      - 37.0.0
    Android NDK: 28.2.13676358
IDEs:
  Android Studio: Not Found
Languages:
  Java:
    version: 17.0.20.1
    path: /usr/bin/javac
  Ruby:
    version: 3.0.2
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react: Not Found
  react-native: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

Stacktrace or Logs

react-native f1f147405888d6ffbcab40e59a05df7aa21ddc7e, committed 2026-10-31T14:33:21+00:00
clang version 23.1.3 (https://github.com/llvm/llvm-project 0d261d1ca552c95a8f007e061c787ac7132fbcbc)
== the stock tester
    Command failed (status code: (empty), signal: SIGSEGV): /react-native/private/react-native-fantom/build/tester/fantom_tester --bundlePath /react-native/private/react-native-fantom/.out/js-builds/run-1793466203344/1793466216285-NativeCrash-itest.js.bundle.js --featureFlags {} --minLogLevel error
    stdout:
    (empty)
    stderr:
    (empty)
== InstallFailureSignalHandler in main
    Command failed (status code: (empty), signal: SIGSEGV): /react-native/private/react-native-fantom/build/tester/fantom_tester --bundlePath /react-native/private/react-native-fantom/.out/js-builds/run-1793466247448/1793466255947-NativeCrash-itest.js.bundle.js --featureFlags {} --minLogLevel error
    stdout:
    (empty)
    stderr:
    (empty)
== and HAVE_SIGACTION in glog's config.h
    Command failed (status code: (empty), signal: SIGSEGV): /react-native/private/react-native-fantom/build/tester/fantom_tester --bundlePath /react-native/private/react-native-fantom/.out/js-builds/run-1793466328130/1793466336202-NativeCrash-itest.js.bundle.js --featureFlags {} --minLogLevel error
    stdout:
    (empty)
    stderr:
    *** Aborted at 1793466337 (unix time) try "date -d @1793466337" if you are using GNU date ***
    PC: @                0x0 (unknown)
    *** SIGSEGV (@0x0) received by PID 12849 (TID 0x7fa6a81aaf00) stack trace: ***
        @     0x7fa6aa33b520 (unknown)
        @     0x5c12e082a256 (unknown)
        @     0x5c12e082a21d (unknown)
        @     0x5c12e0837eac (unknown)
        @     0x5c12e08322e6 (unknown)
        @     0x5c12e083ee70 (unknown)
        @     0x5c12e083ee26 (unknown)
        @     0x5c12e083edb0 (unknown)
        @     0x5c12e083ec70 (unknown)
        @     0x7fa6aaef48d7 (unknown)
        @     0x7fa6ab0b2921 (unknown)
        @     0x7fa6ab0b3230 (unknown)
        @     0x7fa6ab0b2a4f (unknown)
        @     0x7fa6ab097c0d (unknown)
        @     0x7fa6aaee97fb (unknown)
        @     0x5c12e08596f8 (unknown)
        @     0x5c12e0859665 (unknown)
        @     0x5c12e0846b11 (unknown)
        @     0x5c12e084100d (unknown)
        @     0x5c12e08a86a1 (unknown)
        @     0x7fa6aa322d90 (unknown)
        @     0x7fa6aa322e40 (unknown)
        @     0x5c12e0821745 (unknown)
        @                0x0 (unknown)
== and OS_LINUX kept in glog's config.h
    Command failed (status code: (empty), signal: SIGSEGV): /react-native/private/react-native-fantom/build/tester/fantom_tester --bundlePath /react-native/private/react-native-fantom/.out/js-builds/run-1793466481945/1793466501913-NativeCrash-itest.js.bundle.js --featureFlags {} --minLogLevel error
    stdout:
    (empty)
    stderr:
    *** Aborted at 1793466504 (unix time) try "date -d @1793466504" if you are using GNU date ***
    PC: @                0x0 (unknown)
    *** SIGSEGV (@0x0) received by PID 15321 (TID 0x73082173ff00) from PID 0; stack trace: ***
        @     0x7308238d0520 (unknown)
        @     0x58ef9a29c066 facebook::react::faultOnNullWrite()
        @     0x58ef9a29c02d facebook::react::NativeFantom::clearAllImages()
        @     0x58ef9a2a9cbc _ZN8facebook5react8bridging10callFromJsIvNS0_12NativeFantomEvJEJEEET_RNS_3jsi7RuntimeEMT0_FT1_S7_DpT2_ERKSt10shared_ptrINS0_11CallInvokerEEPS8_DpOT3_
        @     0x58ef9a2a40f6 facebook::react::NativeFantomCxxSpec<>::__clearAllImages()
        @     0x58ef9a2b0c80 _ZZN8facebook5react11TurboModule6createERNS_3jsi7RuntimeERKNS2_10PropNameIDEENKUlS4_RKNS2_5ValueEPS9_mE_clES4_SA_SB_m
        @     0x58ef9a2b0c36 _ZSt13__invoke_implIN8facebook3jsi5ValueERZNS0_5react11TurboModule6createERNS1_7RuntimeERKNS1_10PropNameIDEEUlS6_RKS2_PSA_mE_JS6_SB_SC_mEET_St14__invoke_otherOT0_DpOT1_
        @     0x58ef9a2b0bc0 _ZSt10__invoke_rIN8facebook3jsi5ValueERZNS0_5react11TurboModule6createERNS1_7RuntimeERKNS1_10PropNameIDEEUlS6_RKS2_PSA_mE_JS6_SB_SC_mEENSt9enable_ifIX16is_invocable_r_vIT_T0_DpT1_EESG_E4typeEOSH_DpOSI_
        @     0x58ef9a2b0a80 _ZNSt17_Function_handlerIFN8facebook3jsi5ValueERNS1_7RuntimeERKS2_PS5_mEZNS0_5react11TurboModule6createES4_RKNS1_10PropNameIDEEUlS4_S6_S7_mE_E9_M_invokeERKSt9_Any_dataS4_S6_OS7_Om
        @     0x73082448f8d7 facebook::hermes::(anonymous namespace)::HermesRuntimeImpl::HFContext::func()
        @     0x73082464d921 hermes::vm::Interpreter::handleCallSlowPath()
        @     0x73082464e230 hermes::vm::Interpreter::interpretFunction<>()
        @     0x73082464da4f hermes::vm::Runtime::interpretFunctionImpl()
        @     0x730824632c0d hermes::vm::JSFunction::_callImpl()
        @     0x7308244847fb facebook::hermes::(anonymous namespace)::HermesRuntimeImpl::call()
        @     0x58ef9a2cb508 facebook::jsi::Function::call()
        @     0x58ef9a2cb475 facebook::jsi::Function::call()
        @     0x58ef9a2b8921 _ZNK8facebook3jsi8Function4callIJEEENS0_5ValueERNS0_8IRuntimeEDpOT_
        @     0x58ef9a2b2e1d facebook::react::TesterAppDelegate::loadScriptAndRunTests()
        @     0x58ef9a31a4b1 main
        @     0x7308238b7d90 (unknown)
        @     0x7308238b7e40 __libc_start_main
        @     0x58ef9a293555 _start
        @                0x0 (unknown)

MANDATORY Reproducer

https://github.com/YevheniiKotyrlo/react-native-fantom-reproducer

Screenshots and Videos

No response