CONCURRENCY.C_THREAD.SYNCINIT : Synchronization Object Initialized in Worker Thread

Summary

A warning of this class is issued when a worker thread may call one of the following functions:

• C11: mtx_init and cnd_init.
• POSIX: pthread_mutex_init, pthread_cond_init, pthread_rwlock_init, pthread_spin_init, sem_init, and sem_open.
• Windows: InitializeCriticalSection, InitializeCriticalSectionAndSpinCount, InitializeCriticalSectionEx, InitializeConditionVariable, InitializeSRWLock, and the A and W variants of CreateMutex, CreateMutexEx, CreateSemaphore, CreateSemaphoreEx, CreateEvent, and CreateEventEx.
• OpenMP: omp_init_lock and omp_init_nest_lock.
• VxWorks: semBCreate, semCCreate, semMCreate, semBInitialize, semCInitialize, semMInitialize, semCreate, and semOpen.
• FreeRTOS: xQueueCreateMutex, xQueueCreateMutexStatic, xSemaphoreCreateBinary, xSemaphoreCreateBinaryStatic, and vSemaphoreCreateBinary.
• Qt and MFC: the QMutex and CMutex constructors.
• Darwin kernel: hw_lock_init.

Windows mutex, semaphore, and event creation calls, sem_open, semOpen, and the CMutex constructor are reported even if they open an existing named object. The check does not inspect the name or return value to distinguish creation from opening. Other calls that open or operate on existing objects, attribute initialization, and static initializers are not covered.

The check includes calls made through helper functions. Calls made only by the initial thread are not reported.

This check does not determine whether the initialization is safe or whether another thread accesses the object before it is initialized.

Properties

WARNING_FILTER += allow class="Synchronization Object Initialized in Worker Thread"

Example

#include <threads.h>
#include <stdlib.h>

static mtx_t queue_mutex;

static int service_worker(void *) {
    return mtx_init(&queue_mutex, mtx_plain); // 'Synchronization Object Initialized in Worker Thread' warning issued here
}

int main() {
    thrd_t service;
    if (thrd_create(&service, service_worker, 0) != thrd_success)
        abort();
    if (thrd_join(service, 0) != thrd_success)
        abort();
    return 0;
}

To reproduce this example, analyze it with the following configuration:

WARNING_FILTER += allow class="Synchronization Object Initialized in Worker Thread"

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.

• FORCE_THREAD_ENTRY_NAMES
• REPORT_SIMILAR_WARNINGS
• THREAD_ENTRY_METHOD_NAMES
• WARNING_FILTER