Hi everyone,
I was following the Video Modernize PCI and SCSI drivers with DriverKit and the Document to implement UserMapHBAData(), and here’s my current implementation:
// kern_return_t DRV_MAIN_CLASS_NAME::UserMapHBAData_Impl(uint32_t *uniqueTaskID)
kern_return_t IMPL(DRV_MAIN_CLASS_NAME, UserMapHBAData)
{
Log("UserMapHBAData() - Start");
// Define the vm_page_size explicitly
const uint32_t vm_page_size = 4096;
kern_return_t ret;
IOBufferMemoryDescriptor *buffer = nullptr;
IOMemoryMap *memMap = nullptr;
void *taskData = nullptr;
// Create a buffer for HBA-specific task data
ret = IOBufferMemoryDescriptor::Create(kIOMemoryDirectionOutIn, ivars->fTaskDataSize, vm_page_size, &buffer);
__Require((kIOReturnSuccess == ret), Exit);
// Map memory to the driver extension's memory space
ret = buffer->CreateMapping(0, 0, 0, 0, 0, &memMap);
__Require((kIOReturnSuccess == ret), Exit);
// Retrieve mapped memory address
taskData = reinterpret_cast<void *>(memMap->GetAddress());
__Require(taskData, Exit);
// WARNING: Potential leak of an object stored into 'buffer'
// WARNING: Potential leak of an object stored into 'memMap'
// Assign a unique task ID
ivars->fTaskID++; // ERROR: No member named 'fTaskID' in 'DriverKitAcxxx_IVars'
ivars->fTaskArray[ivars->fTaskID] = taskData;
*uniqueTaskID = ivars->fTaskID;
Log("UserMapHBAData() - End");
return kIOReturnSuccess;
Exit:
// Cleanup in case of failure
if (memMap) {
memMap->free(); // Correct method for releasing memory maps
}
if (buffer) {
buffer->free(); // Correct method for releasing buffer memory
}
LogErr("ret = 0x%0x", ret);
Log("UserMapHBAData() - End");
return ret;
}
For reference, in KEXT, memory allocation is typically done using:
IOBufferMemoryDescriptor *buffer = IOBufferMemoryDescriptor::inTaskWithOptions(
kernel_task, // Task in which memory is allocated
kIODirectionOutIn, // Direction (read/write)
1024, // Size of the buffer in bytes
4); // Alignment requirements
However, after installing the dext, macOS hangs, and I have to do a hardware reset. After rebooting, the sysctl list output shows:
% sectl list
1 extension(s)
--- com.apple.system_extension.driver_extension
enabled active teamID bundleID (version) name [state]
* - com.accusys.DriverKitAcxxx (5.0/11) com.accusys.DriverKitAcxxx [activated waiting for user]
Questions:
What could be causing macOS to halt?
How should I approach debugging and resolving this issue?
Looking forward to your insights, any suggestions would be greatly appreciated!
Best regards, Charles
