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Analyzing native crashes on Android

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Mark Tehver edited this page Mar 7, 2022 · 1 revision

Native crashes on Android are hard to analyze. Logcat may contain lines like this:

#00 pc 00000000002d484c /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000002d2699 /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000001f605d /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000001d1fe1 /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000001bf8d3 /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000001baa75 /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 0000000000210b23 /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000001e9a77 /data/app/~~gAdohKsYsR7ns_m6FQWiYA==/lib/arm/libcarto_mobile_sdk.so
#00 pc 00000000000b0547 /apex/com.android.runtime/lib/bionic/libc.so (__pthread_start(void*)+40)
#00 pc 0000000000066b17 /apex/com.android.runtime/lib/bionic/libc.so (__start_thread+30)

This is a native stack trace but usually not very helpful, as it contains only native addresses. These addresses can be mapped to source code locations, though, by creating a duplicate build with full symbol info. We keep such builds for official SDK releases starting from SDK 4.4.5.

For custom builds, the following steps can be used:

  • add -g flag to CMAKE_C_FLAGS_RELEASE and CMAKE_CXX_FLAGS_RELEASE in scripts/build/CMakeLists.txt
  • replace -s flag with -g flag in CMAKE_SHARED_LINKER_FLAGS_RELEASE
  • remove -Wl,--build-id flag from CMAKE_SHARED_LINKER_FLAGS_RELEASE
  • after the changes SDK should be built following the instructions in the building guide
  • copy carto_mobile_sdk.so files found under build/android-arm64-v8a and build/android-armeabi-v7a directories to a separate location. These files are relatively large (200-500MB) and contain full debug symbol info needed for matching native addresses to source code locations.
  • drop all the changes made in scripts/build/CMakeLists.txt, restore original file state
  • remove -Wl,--build-id flag from CMAKE_SHARED_LINKER_FLAGS_RELEASE again
  • build the SDK again by following the instructions in the building guide. This build does not contain any debug symbol info but can be matched with the previously generated carto_mobile_sdk.so files.

When analyzing native crashes, ndk-stack utility from Android NDK can be used afterwards:

cat crashlog.txt | ndk-stack -sym PATH_TO_DIRECTORY_CONTAINING_CARTO_MOBILE_SDK_SO_FILE

Detailed instructions can be found here.

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