[FR] Missing TSAN runtime support?

[equeim]

Description

Add -fsanitize=thread to compile and link flags, and get error: undefined reference to '__tsan_func_entry' (and other tsan functions) link errors.

Environment Details

• NDK Version: 20.0.5594570
• Build system: CMake
• Host OS: Ubuntu 18.04
• ABI: arm64-v8a
• NDK API level: 21
• Device API level: 28

[enh]

i know @yabinc had this working (for the platform) at one point, but it may have bitrotted. @eugenis might also know something useful...

[eugenis]

That's basically all I know. Upstream tests are disabled (and AFAIK have never been enabled), so it is likely broken at this point.

[stephenhines]

TSan was never released in the NDK, so this is more of a feature request. @yabinc did have it working in the platform, but there are other components that would be needed in the NDK to actually let app developers enable it.

[yabinc]

TSAN uses a TLS slot to store thread specific state. Bionic added that support in Android N as slot 8, but changed to slot 6 in Android Q. The tsan library still uses slot 8.
So currently the platform tsan is broken. I think we need to add dynamic detection of android version in tsan library.

To use tsan on android, we need a tsan shared library linked and available on device, as https://android-review.googlesource.com/c/platform/prebuilts/clang/host/linux-x86/+/516421/1/Android.bp#253. static linking libtsan might also be possible, I didn't remember why we chose to use shared library.

llvm-symbolizer is also needed on device to report data race locations.

[equeim]

asan and ubsan have shared libraries in ndk, which can be bundled with apps. tsan for some reason has only static library.

[haolongzhangm]

aarch64-linux-android-clang++ -fsanitize=thread -O0 -fno-omit-frame-pointer -g -pie -fPIE -L/home/zhl/mycode/tmp_aosp_for_tsan/aosp/prebuilts/clang/host/./linux-x86/clang-r349610b/lib64/clang/8.0.9/lib/linux/ -lclang_rt.tsan-aarch64-android main.cc -o android_test_tsan

tsan_interceptors.cc:1747: undefined reference to `fileno_unlocked'

extern "C" int fileno_unlocked(void *stream); at tsan_interceptors.cc

but fileno_unlocked defined in libc:
int fileno_unlocked(FILE* __fp)

[haolongzhangm]

issue same libclang_rt.tsan-aarch64-android.a link a different version of libc with NDK default libc.so?

int fileno_unlocked(FILE* __fp)
int fileno_unlocked(void *stream)

different args ?

any idea about this? rebuild NDK?

[DanAlbert]

Rebuilding will just rebuild the bug. TSan needs to be fixed to work for Android. This isn't currently supported.