CONCURRENCY.C_ATOMIC.INIT : Inappropriate C Atomic Initialization

An atomic variable is accessed, but it has not been initialized. There are two cases:

A non-initializing assignment into an atomic variable.

Taking the address of an uninitialized atomic variable (because this may be subsequently used to assign into the variable).

For the sake of this check, a variable is considered to be atomic if it is declared with the _Atomic type specifier or has any atomic type defined in <stdatomic.h>.

Note: if an atomic variable is used without being initialized, CodeSonar will issue an Uninitialized Variable warning.

Properties

Class Name

Inappropriate C Atomic Initialization

Significance

reliability

Mnemonic

CONCURRENCY.C_ATOMIC.INIT

Categories

MisraC2023	MisraC2023:1.3	There shall be no occurrence of undefined or critical unspecified behaviour
	MisraC2023:9.7	Atomic objects shall be appropriately initialized before being accessed
Misra2012	Misra2012:1.3	There shall be no occurrence of undefined or critical unspecified behaviour
	Misra2012:9.7	Atomic objects shall be appropriately initialized before being accessed
CWE	CWE:665	Improper Initialization
	CWE:908	Use of Uninitialized Resource

Availability

Available for C and C++.

Enabling

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

WARNING_FILTER += discard class="Inappropriate C Atomic Initialization"

Example

#include <stdint.h>
#include <stdatomic.h>

int32_t concurrency_c_atomic_init( void ){
    _Atomic int32_t good1 = 111;                               /* ok: direct initialization */
    _Atomic int32_t good2;
    int32_t _Atomic * goodp;
    _Atomic int32_t bad1;
    _Atomic int32_t bad2;
    _Atomic int32_t bad3;
    int32_t _Atomic * badp;

    atomic_init(&good2, 222);                                 /* ok: initialization with atomic_init() */

    good1 = 555;                                              /* ok: good1 previously initialized */
    goodp = &good2;                                           /* ok: good2 previously initialized */

    bad1 = 333;                       /* 'Inappropriate C Atomic Initialization' warning issued here
                                       *  - not direct initialization and not using atomic_init()
                                       */
    badp = &bad2;                     /* 'Inappropriate C Atomic Initialization' warning issued here
                                       * - taking address of uninitialized atomic variable
                                       */
    *badp = 444;                      /* 'Inappropriate C Atomic Initialization' warning issued here
                                       * - writing through pointer into uninitialized atomic variable
                                       */

    return bad3;                               /* 'Uninitialized Variable' warning issued here
                                                * - use of ininitialized atomic variable
                                                */
}

Relevant Configuration File Parameters

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