test_mutex_timeout_race.c File Reference

#include <zephyr/ztest.h>

Macros
#define	TIMEOUT_MS   100
#define	STACKSZ   8192

Functions
	K_THREAD_STACK_DEFINE (stack, 8192)
static void	test_thread (void *p1, void *p2, void *p3)
	ZTEST (mutex_timeout_race_during_priority_inversion, test_mutex_timeout_error)
	Test fix for subtle race during priority inversion. More...
	ZTEST_SUITE (mutex_timeout_race_during_priority_inversion, NULL, NULL, NULL, NULL, NULL)

Variables
static struct k_mutex	mutex
static struct k_thread	thread

Macro Definition Documentation

STACKSZ

#define STACKSZ   8192

TIMEOUT_MS

#define TIMEOUT_MS   100

Function Documentation

K_THREAD_STACK_DEFINE()

K_THREAD_STACK_DEFINE	(	stack	,
		8192
	)

test_thread()

static void test_thread ( void *  p1, void *  p2, void *  p3  )

static

ZTEST()

ZTEST	(	mutex_timeout_race_during_priority_inversion	,
		test_mutex_timeout_error
	)

Test fix for subtle race during priority inversion.

• A low priority thread (Tlow) locks mutex A.
• A high priority thread (Thigh) blocks on mutex A, boosting the priority of Tlow.
• Thigh times out waiting for mutex A.
• Before Thigh has a chance to execute, Tlow unlocks mutex A (which now has no owner) and drops its own priority.
• Thigh now gets a chance to execute and finds that it timed out, and then enters the block of code to lower the priority of the thread that owns mutex A (now nobody).
• Thigh tries to the dereference the owner of mutex A (which is nobody, and thus it is NULL). This leads to an exception.

See also

k_mutex_lock()

ZTEST_SUITE()

ZTEST_SUITE	(	mutex_timeout_race_during_priority_inversion	,
		NULL	,
		NULL	,
		NULL	,
		NULL	,
		NULL
	)

Variable Documentation

mutex

struct k_mutex mutex

static

thread

struct k_thread thread

static