CONCURRENCY.LOCK.TWICE : Locked Twice

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CodeSonar^® 9.2p0

CONFIDENTIAL

CodeSecure Inc

C and C++

CONCURRENCY.LOCK.TWICE : Locked Twice

Summary

An attempt to acquire a lock when the lock is already held. This can lead to deadlock or other undefined behavior.

Properties

Class Name

Locked Twice

Significance

reliability

Mnemonic

CONCURRENCY.LOCK.TWICE

Categories

MisraC2025	MisraC2025:22.18	Non-recursive mutexes shall not be recursively locked
MisraC2023	MisraC2023:22.18	Non-recursive mutexes shall not be recursively locked
Misra2012	Misra2012:22.18	Non-recursive mutexes shall not be recursively locked
CWE	CWE:764	Multiple Locks of a Critical Resource
JPL	JPL:9	Place restrictions on the use of semaphores and locks.

Availability

Available for C and C++.

Enabling

Checks for this warning class are disabled by default. To enable them, add the following WARNING_FILTER rule to the project configuration file.

WARNING_FILTER += allow class="Locked Twice"

Triggering Functions

Locked Twice warnings can be triggered by the following functions.

Any function treated as a lock acquisition function by CodeSonar:
- any library function that is recognized as a lock acquisition function because CodeSonar ships with a library model that identifies it as such, and
- any function for which you have added a library model identifying it as a lock acquisition function.
Any function specified with the LOCK_FUNCTIONS configuration file parameter.

Example

#include <pthread.h>

pthread_mutex_t LockA;
pthread_mutex_t LockB;

void LOCK_TWICE(void){
    pthread_mutex_lock(&LockA);
    pthread_mutex_lock(&LockB);
    pthread_mutex_lock(&LockA); /* 'Locked Twice' warning issued here */
                                /* 'Double Lock' warning also issued if enabled */
    /* ... operate on locked data */
    pthread_mutex_unlock(&LockA);
    pthread_mutex_unlock(&LockB);
}

Relevant Configuration File Parameters

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

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