HIGH: Memory Leak Potential from Raw Pointer Usage Without Proper Cleanup

[juliensimon]

Issue Description

Memory safety issue: Raw pointer usage without proper cleanup mechanisms in platform factory and related components, creating potential for memory leaks and resource exhaustion.

Location

File: common/platform_factory.cpp
Lines: 78-92 (platform creation and management functions)
Related Areas:

• Platform interface implementations
• Resource management in factory pattern
• Memory cleanup in destructors

Safety Impact

• Severity: HIGH (P1)
• Risk: Memory leaks, resource exhaustion, system instability
• Attack Vector: Repeated object creation without cleanup
• Stability Risk: High - can cause long-running processes to consume excessive memory

Technical Details

Current Implementation Analysis

Based on the factory pattern in platform_factory.cpp:

// Current implementation (lines 16-32)
std::unique_ptr<PlatformInterface> create_platform_interface() {
#ifdef __APPLE__
    return std::make_unique<MacOSPlatform>();
#elif defined(__linux__)
    #if defined(__x86_64__) || defined(__amd64__)
    return std::make_unique<IntelPlatform>();
    #elif defined(__aarch64__)
    return std::make_unique<ARM64Platform>();
    #endif
#endif
}

Potential Memory Leak Sources

1. Resource allocation in platform constructors may not be properly cleaned up
2. Exception during construction can leave resources partially allocated
3. Platform-specific resources (hardware handles, system resources) may not be released
4. Circular references between platform objects and their dependencies
5. Static resource management without proper cleanup on program termination

Expected Behavior

• All allocated resources should have guaranteed cleanup
• Exception-safe resource management (RAII)
• No memory leaks in repeated platform creation/destruction
• Proper cleanup of platform-specific resources
• Deterministic resource deallocation

Actual Behavior

• Potential memory leaks from incomplete resource cleanup
• Platform-specific resources may not be properly released
• Exception scenarios may leave resources allocated
• Long-running processes may accumulate leaked memory

Steps to Reproduce

Memory Leak Detection

# Build with leak detection
make CXXFLAGS="-fsanitize=leak -g" clean all

# Run leak detection test
./memory_bandwidth --cache-hierarchy

# Expected output with leaks:
# SUMMARY: LeakSanitizer: X bytes in Y allocations

# Valgrind detection
valgrind --leak-check=full --show-leak-kinds=all ./memory_bandwidth

# Expected: Memory leak reports if present

Stress Test for Leaks

// Test repeated platform creation/destruction
int main() {
    for (int i = 0; i < 10000; ++i) {
        auto platform = create_platform_interface();
        // Perform some operations
        platform->get_cache_hierarchy();
        // Platform destructor should clean up everything
    }
    // Memory usage should return to baseline
}

Memory Leak Analysis

Potential Leak Sources in Platform Objects

// Hypothetical problematic patterns

class MacOSPlatform : public PlatformInterface {
private:
    // Potential leak sources:
    void* hardware_context_;        // Raw pointer to system resource
    std::vector<uint8_t*> buffers_; // Raw pointers without cleanup
    FILE* debug_log_file_;          // File handle without RAII
    
public:
    MacOSPlatform() {
        hardware_context_ = allocate_hardware_context();  // May throw
        debug_log_file_ = fopen("debug.log", "w");        // May fail
        
        // If exception thrown here, previous resources leak
        initialize_buffers();
    }
    
    ~MacOSPlatform() {
        // Destructor may not be called if constructor throws
        if (hardware_context_) {
            free_hardware_context(hardware_context_);
        }
        if (debug_log_file_) {
            fclose(debug_log_file_);
        }
        // Missing cleanup for buffers_
    }
};

Suggested Solution

// Memory-safe platform factory with RAII and proper cleanup

// 1. RAII wrapper for platform-specific resources
template<typename T, void(*Deleter)(T*)>
class RAIIResource {
private:
    T* resource_;
    
public:
    explicit RAIIResource(T* resource) : resource_(resource) {}
    
    ~RAIIResource() {
        if (resource_) {
            Deleter(resource_);
        }
    }
    
    RAIIResource(const RAIIResource&) = delete;
    RAIIResource& operator=(const RAIIResource&) = delete;
    
    RAIIResource(RAIIResource&& other) noexcept : resource_(other.resource_) {
        other.resource_ = nullptr;
    }
    
    RAIIResource& operator=(RAIIResource&& other) noexcept {
        if (this != &other) {
            if (resource_) {
                Deleter(resource_);
            }
            resource_ = other.resource_;
            other.resource_ = nullptr;
        }
        return *this;
    }
    
    T* get() const { return resource_; }
    T* release() {
        T* temp = resource_;
        resource_ = nullptr;
        return temp;
    }
};

// 2. Exception-safe platform implementation
class SafeMacOSPlatform : public PlatformInterface {
private:
    // RAII resource management
    std::unique_ptr<HardwareContext, HardwareContextDeleter> hardware_context_;
    std::unique_ptr<FILE, decltype(&fclose)> debug_log_file_;
    std::vector<std::unique_ptr<uint8_t[]>> managed_buffers_;
    
public:
    SafeMacOSPlatform() 
        : hardware_context_(nullptr, HardwareContextDeleter{})
        , debug_log_file_(nullptr, &fclose) {
        
        // Exception-safe initialization
        try {
            // Step 1: Allocate hardware context
            auto* ctx = allocate_hardware_context();
            if (!ctx) {
                throw PlatformError("Failed to allocate hardware context");
            }
            hardware_context_.reset(ctx);
            
            // Step 2: Open debug log file
            FILE* log_file = fopen("debug.log", "w");
            if (!log_file) {
                throw PlatformError("Failed to open debug log file");
            }
            debug_log_file_.reset(log_file);
            
            // Step 3: Initialize buffers
            initialize_managed_buffers();
            
            // All resources are now managed by RAII
        } catch (...) {
            // RAII destructors will clean up any successfully allocated resources
            throw;
        }
    }
    
    ~SafeMacOSPlatform() {
        // All cleanup handled automatically by RAII wrappers
        // No manual cleanup needed - exception safe
    }
    
private:
    void initialize_managed_buffers() {
        const size_t buffer_count = 10;
        const size_t buffer_size = 1024;
        
        managed_buffers_.reserve(buffer_count);
        
        for (size_t i = 0; i < buffer_count; ++i) {
            auto buffer = std::make_unique<uint8_t[]>(buffer_size);
            if (!buffer) {
                throw std::bad_alloc();
            }
            managed_buffers_.push_back(std::move(buffer));
        }
    }
    
    struct HardwareContextDeleter {
        void operator()(HardwareContext* ctx) {
            if (ctx) {
                free_hardware_context(ctx);
            }
        }
    };
};

// 3. Memory leak detection and monitoring
class ResourceMonitor {
private:
    static std::atomic<size_t> active_platforms_;
    static std::atomic<size_t> total_allocations_;
    
public:
    static void platform_created() {
        active_platforms_++;
        total_allocations_++;
    }
    
    static void platform_destroyed() {
        active_platforms_--;
    }
    
    static void check_for_leaks() {
        if (active_platforms_ > 0) {
            std::cerr << "WARNING: " << active_platforms_ 
                     << " platform objects still active (potential leak)" << std::endl;
        }
    }
    
    static void print_statistics() {
        std::cout << "Platform Statistics:" << std::endl;
        std::cout << "  Total created: " << total_allocations_ << std::endl;
        std::cout << "  Still active: " << active_platforms_ << std::endl;
        std::cout << "  Properly cleaned up: " << (total_allocations_ - active_platforms_) << std::endl;
    }
};

// 4. Enhanced factory with leak detection
class LeakSafePlatformFactory {
public:
    static std::unique_ptr<PlatformInterface> create_platform_interface() {
        ResourceMonitor::platform_created();
        
        try {
#ifdef __APPLE__
            auto platform = std::make_unique<SafeMacOSPlatform>();
            return std::unique_ptr<PlatformInterface>(platform.release());
#elif defined(__linux__)
    #if defined(__x86_64__) || defined(__amd64__)
            auto platform = std::make_unique<SafeIntelPlatform>();
            return std::unique_ptr<PlatformInterface>(platform.release());
    #endif
#endif
        } catch (...) {
            ResourceMonitor::platform_destroyed(); // Decrement on failure
            throw;
        }
    }
    
    // Custom deleter that tracks destruction
    class PlatformDeleter {
    public:
        void operator()(PlatformInterface* platform) {
            ResourceMonitor::platform_destroyed();
            delete platform;
        }
    };
    
    static std::unique_ptr<PlatformInterface, PlatformDeleter> 
    create_tracked_platform() {
        auto platform = create_platform_interface();
        return std::unique_ptr<PlatformInterface, PlatformDeleter>(
            platform.release(), PlatformDeleter{});
    }
};

// 5. Program termination leak check
class LeakChecker {
public:
    ~LeakChecker() {
        ResourceMonitor::check_for_leaks();
        ResourceMonitor::print_statistics();
    }
};

// Install global leak checker
static LeakChecker global_leak_checker;

Acceptance Criteria

• Replace all raw pointer usage with RAII-managed resources
• Implement exception-safe resource management in all platform classes
• Add automatic memory leak detection and monitoring
• Ensure zero memory leaks in repeated creation/destruction cycles
• Add comprehensive memory leak testing with sanitizers
• Validate proper cleanup of platform-specific resources
• Test exception scenarios for resource cleanup

Testing Requirements

• Memory leak detection with AddressSanitizer/LeakSanitizer
• Valgrind memory leak testing
• Stress testing with repeated object creation/destruction
• Exception testing during resource allocation
• Long-running process memory stability testing
• Platform-specific resource cleanup verification

Memory Safety Validation

# Comprehensive leak testing
make CXXFLAGS="-fsanitize=address -fsanitize=leak -g" clean all

# Stress test for leaks
./stress_test_platforms 10000  # Create/destroy 10000 platforms

# Valgrind comprehensive check
valgrind --leak-check=full --track-origins=yes --show-leak-kinds=all \
         ./memory_bandwidth --cache-hierarchy

# Expected: Zero leaks reported

Performance Impact Analysis

// Benchmark memory usage over time
void benchmark_memory_stability() {
    size_t baseline_memory = get_process_memory_usage();
    
    for (int i = 0; i < 1000; ++i) {
        auto platform = create_platform_interface();
        platform->perform_operations();
        // Platform should be fully cleaned up here
        
        if (i % 100 == 0) {
            size_t current_memory = get_process_memory_usage();
            if (current_memory > baseline_memory * 1.1) {
                std::cerr << "Memory leak detected at iteration " << i << std::endl;
                break;
            }
        }
    }
}

Expected Memory Safety Improvements

• Memory leak elimination: 100% cleanup of allocated resources
• Exception safety: No resource leaks during exception scenarios
• Long-running stability: Stable memory usage over time
• Resource efficiency: Optimal resource utilization
• Debugging capability: Clear leak detection and reporting

References

• C++ Core Guidelines: Resource Management
• RAII (Resource Acquisition Is Initialization) Best Practices
• Exception Safety in C++
• Memory Leak Detection Techniques

Priority: HIGH - Critical for system stability and resource management
Estimated Effort: 4-5 days
Memory Safety Review Required: Yes