NVTX v3 dynamic library segfaults during initialization on Windows

[maleadt]

I'm using NVTX from Julia, so I compile NVTX into a shared library as documented in https://github.com/NVIDIA/NVTX?tab=readme-ov-file#other-languages. This works fine on most platforms, but on Windows (where we build our binaries using MinGW compilers) NVTX segfaults during initialization. This reproduces in C, so doesn't look like a Julia issue. I'm using msys2 on Window 11, with the compilers from the mingw-w64-x86_64-toolchain package.

To generate nvToolsExt.dll, I do:

$ git clone https://github.com/NVIDIA/NVTX -b dev

$ cat >nvtx.c <<EOD
#define NVTX_EXPORT_API
#include <nvtx3/nvToolsExt.h>
#include <nvtx3/nvToolsExtCuda.h>
EOD

$ cc -g -shared -I /path/to/cuda/include -I ./c/include -o nvToolsExt.dll nvtx.c

To simulate what we do in Julia, I'm using the following simple loader:

#include <stdio.h>
#include <windows.h>

typedef void (*NvtxInitializeFunc)(void*);

int main() {
    // Load the DLL
    HMODULE hLib = LoadLibraryA("nvToolsExt.dll");
    if (hLib == NULL) {
        fprintf(stderr, "Failed to load libnvToolsExt.dll. Error code: %lu\n", GetLastError());
        return 1;
    }

    // Get the function pointer
    NvtxInitializeFunc nvtxInitialize = (NvtxInitializeFunc)GetProcAddress(hLib, "nvtxInitialize");
    if (nvtxInitialize == NULL) {
        fprintf(stderr, "Failed to get nvtxInitialize function. Error code: %lu\n", GetLastError());
        FreeLibrary(hLib);
        return 1;
    }

    // Call the function with NULL parameter
    nvtxInitialize(NULL);

    // Clean up
    FreeLibrary(hLib);

    return 0;
}

$ cc -g loader.c -o loader && ./loader.exe
zsh: segmentation fault  ./loader.exe

GDB reveals it indeed fails during initialization:

(gdb) bt
#0  0x00007ffcaa134a7e in ?? ()
#1  0x00007ffcaa131a0f in nvtxInitialize (reserved=0x0) at ./c/include/nvtx3/nvtxDetail/nvtxImplCore.h:317
#2  0x00007ff60c631508 in main () at loader.c:23

x-ref JuliaGPU/NVTX.jl#37, also filed as NVIDIA bug 4262590.

[evanramos-nvidia]

nvToolsExt.dll is deprecated as of NVTXv3. Work is in progress to create a replacement DLL for cross-language interoperability. We will keep you updated.

[maleadt]

nvToolsExt.dll is deprecated

I'm building my own version based on the code in this repository, it only happens to have the same name:

To generate nvToolsExt.dll, I do:

$ git clone https://github.com/NVIDIA/NVTX -b dev

$ cat >nvtx.c <<EOD
#define NVTX_EXPORT_API
#include <nvtx3/nvToolsExt.h>
#include <nvtx3/nvToolsExtCuda.h>
EOD

$ cc -g -shared -I /path/to/cuda/include -I ./c/include -o nvToolsExt.dll nvtx.c

[evanramos-nvidia]

Thanks for your report. A fix for building with NVTX_EXPORT_API is in progress (the same task I mentioned for a new DLL).

[maleadt]

Any branch I could test, or isn't the work public yet?