egl-segfault for NVIDIA/nvidia-docker#146

README.md

Demonstrates segfault if libEGL.so does not exist. Creating a symlink pointing to libEGL.so.1 resolves this. Issue appears to be that libcuda dlopens libEGL.so instead of libEGL.so.1.

See: https://devtalk.nvidia.com/default/topic/917987/cuda-opengl-interoperability-segfault-using-egl-opengl-context-egl_platform_device_ext-/

And: NVIDIA/nvidia-docker#146

To compile:

g++ egl-segfault.cpp -o egl-segfault -lEGL -I/usr/local/cuda-8.0/include/ -lcuda

Program should simply exit successfully. Will segfault if libEGL.so does not exist.

egl-segfault.cpp

#define EGL_EGLEXT_PROTOTYPES // for EGL extensions

#include <GL/gl.h>
#include <EGL/egl.h>
#include <EGL/eglext.h>

#include <cuda.h>
#include <cudaGL.h>

static const EGLint configAttribs[] = {
    EGL_SURFACE_TYPE,    EGL_PBUFFER_BIT, EGL_BLUE_SIZE,  8, EGL_GREEN_SIZE, 8,
    EGL_RED_SIZE,        8,               EGL_ALPHA_SIZE, 8,
    // EGL_DEPTH_SIZE,
    // 8,
    EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,  EGL_NONE};

static const int pbufferWidth = 1024;
static const int pbufferHeight = 1024;

static const EGLint pbufferAttribs[] = {
    EGL_WIDTH, pbufferWidth, EGL_HEIGHT, pbufferHeight, EGL_NONE,
};

static const EGLint contextAttribs[] = {
    EGL_CONTEXT_MAJOR_VERSION,       4,
    EGL_CONTEXT_MINOR_VERSION,       5,
    EGL_CONTEXT_OPENGL_PROFILE_MASK, EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT,
    EGL_NONE,
};

int main(int argc, char *argv[]) {
  // 1. Initialize EGL

  static const int MAX_DEVICES = 4;
  EGLDeviceEXT eglDevs[MAX_DEVICES];
  EGLint numDevices;

  PFNEGLQUERYDEVICESEXTPROC eglQueryDevicesEXT =
      (PFNEGLQUERYDEVICESEXTPROC)eglGetProcAddress("eglQueryDevicesEXT");

  eglQueryDevicesEXT(MAX_DEVICES, eglDevs, &numDevices);

  PFNEGLGETPLATFORMDISPLAYEXTPROC eglGetPlatformDisplayEXT =
      (PFNEGLGETPLATFORMDISPLAYEXTPROC)eglGetProcAddress(
          "eglGetPlatformDisplayEXT");

  EGLDisplay eglDpy =
      eglGetPlatformDisplayEXT(EGL_PLATFORM_DEVICE_EXT, eglDevs[0], 0);

  PFNEGLQUERYDEVICEATTRIBEXTPROC eglQueryDeviceAttribEXT =
      (PFNEGLQUERYDEVICEATTRIBEXTPROC)eglGetProcAddress(
          "eglQueryDeviceAttribEXT");

  int deviceId = -1;
  eglQueryDeviceAttribEXT(eglDevs[0], EGL_CUDA_DEVICE_NV,
                          reinterpret_cast<EGLAttrib *>(&deviceId));

  EGLint major, minor;

  eglInitialize(eglDpy, &major, &minor);

  // 2. Select an appropriate configuration
  EGLint numConfigs;
  EGLConfig eglCfg;

  eglChooseConfig(eglDpy, configAttribs, &eglCfg, 1, &numConfigs);

  // 3. Create a surface
  EGLSurface eglSurf = eglCreatePbufferSurface(eglDpy, eglCfg, pbufferAttribs);

  // 4. Bind the API
  eglBindAPI(EGL_OPENGL_API);

  // 5. Create a context and make it current
  EGLContext eglCtx =
      eglCreateContext(eglDpy, eglCfg, EGL_NO_CONTEXT, contextAttribs);

  eglMakeCurrent(eglDpy, eglSurf, eglSurf, eglCtx);

  cuInit(0);
  unsigned int cudaDeviceCnt = 0;
  unsigned int maxCudaDeviceCnt = 10;
  CUdevice cudaDevices[10];
  cuGLGetDevices(&cudaDeviceCnt, cudaDevices, maxCudaDeviceCnt,
                 CU_GL_DEVICE_LIST_ALL);

  // the above cuGLGetDevices() call segfaults every time. It works with an
  // OpenGL context created via GLX

  return 0;
}