[Offload] Segmentation fault when calling `olGetDeviceInfoSize` for host device name

[leandrolcampos]

A segmentation fault occurs when calling olGetDeviceInfoSize to retrieve the size of the device name for the host device.

The crash happens specifically when olGetDeviceInfoSize is called with OL_DEVICE_INFO_NAME for the host device handle.

Steps to Reproduce:

1. Compile the C++ code snippet provided below using Clang and linking against the LLVMOffload library.

   $ clang++ -std=c++17 host.cpp -I"$LLVM_HOME/include" -L"$LLVM_HOME/lib" -lLLVMOffload -ldl -lpthread -Wl,-rpath,"$LLVM_HOME/lib" -o host

2. Execute the compiled program:

   $ ./host

3. Observe the output.

Program Output:

Getting the storage size of the device name...
Segmentation fault (core dumped)

Code Snippet:

#include <iostream>
#include <offload/OffloadAPI.h>
#include <string>

ol_device_handle_t getHostDevice() {
  static ol_device_handle_t HostDevice = nullptr;

  if (!HostDevice) {
    olIterateDevices(
        [](ol_device_handle_t D, void *Data) {
          ol_platform_handle_t Platform;
          olGetDeviceInfo(D, OL_DEVICE_INFO_PLATFORM, sizeof(Platform),
                          &Platform);
          ol_platform_backend_t Backend;
          olGetPlatformInfo(Platform, OL_PLATFORM_INFO_BACKEND, sizeof(Backend),
                            &Backend);

          if (Backend == OL_PLATFORM_BACKEND_HOST) {
            *(static_cast<ol_device_handle_t *>(Data)) = D;
            return false;
          }

          return true;
        },
        &HostDevice);
  }

  return HostDevice;
}

int main() {
  olInit();

  auto HostDevice = getHostDevice();
  if (HostDevice == nullptr) {
    std::cout << "Host device not found." << std::endl;
    return 1;
  }

  std::cout << "Getting the storage size of the device name..." << std::endl;
  size_t Size = 0;
  olGetDeviceInfoSize(HostDevice, OL_DEVICE_INFO_NAME, &Size);

  std::cout << "Getting the device name..." << std::endl;
  std::string Name(Size, '\0');
  olGetDeviceInfo(HostDevice, OL_DEVICE_INFO_NAME, Size, Name.data());
  Name.pop_back();

  std::cout << "Device name: " << Name << std::endl;

  olShutDown();
  return 0;
}

Environment:

• LLVM version: Custom build from git
  • LLVM Project Commit Hash: 1e4841881ef89aeee77cbf081de42af376bfa3fb
• Operating System: Ubuntu 24.04.2 LTS (WSL2)

[llvmbot]

@llvm/issue-subscribers-offload

Author: Leandro Lacerda Campos (leandrolcampos)

A segmentation fault occurs when calling `olGetDeviceInfoSize` to retrieve the size of the device name for the host device.

The crash happens specifically when olGetDeviceInfoSize is called with OL_DEVICE_INFO_NAME for the host device handle.

Steps to Reproduce:

1. Compile the C++ code snippet provided below using Clang and linking against the LLVMOffload library.

   $ clang++ -std=c++17 host.cpp -I"$LLVM_HOME/include" -L"$LLVM_HOME/lib" -lLLVMOffload -ldl -lpthread -Wl,-rpath,"$LLVM_HOME/lib" -o host

2. Execute the compiled program:

   $ ./host

3. Observe the output.

Program Output:

Getting the storage size of the device name...
Segmentation fault (core dumped)

Code Snippet:

#include <iostream>
#include <offload/OffloadAPI.h>
#include <string>

ol_device_handle_t getHostDevice() {
  static ol_device_handle_t HostDevice = nullptr;

  if (!HostDevice) {
    olIterateDevices(
        [](ol_device_handle_t D, void *Data) {
          ol_platform_handle_t Platform;
          olGetDeviceInfo(D, OL_DEVICE_INFO_PLATFORM, sizeof(Platform),
                          &Platform);
          ol_platform_backend_t Backend;
          olGetPlatformInfo(Platform, OL_PLATFORM_INFO_BACKEND, sizeof(Backend),
                            &Backend);

          if (Backend == OL_PLATFORM_BACKEND_HOST) {
            *(static_cast<ol_device_handle_t *>(Data)) = D;
            return false;
          }

          return true;
        },
        &HostDevice);
  }

  return HostDevice;
}

int main() {
  olInit();

  auto HostDevice = getHostDevice();
  if (HostDevice == nullptr) {
    std::cout << "Host device not found." << std::endl;
    return 1;
  }

  std::cout << "Getting the storage size of the device name..." << std::endl;
  size_t Size = 0;
  olGetDeviceInfoSize(HostDevice, OL_DEVICE_INFO_NAME, &Size);

  std::cout << "Getting the device name..." << std::endl;
  std::string Name(Size, '\0');
  olGetDeviceInfo(HostDevice, OL_DEVICE_INFO_NAME, Size, Name.data());
  Name.pop_back();

  std::cout << "Device name: " << Name << std::endl;

  olShutDown();
  return 0;
}

Environment:

• LLVM version: Custom build from git
  • LLVM Project Commit Hash: 1e4841881ef89aeee77cbf081de42af376bfa3fb
• Operating System: Ubuntu 24.04.2 LTS (WSL2)