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Test a race condition between isc_timer_purge() and isc_event_free()

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Let basic_tick() of 'task1' and 'basic_quick' of 'task4' run in
different threads, and insert an artificial delay in timer_purge()
to cause an existing race condition to appear.
This commit is contained in:
Aram Sargsyan
2024-04-05 14:05:40 +00:00
parent c7b15f1f5a
commit 857f6adaec
2 changed files with 65 additions and 12 deletions
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3
lib/isc/timer.c
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@@ -232,6 +232,9 @@ timer_purge(isc_timer_t *timer) {
while ((event = ISC_LIST_HEAD(timer->active)) != NULL) {
timerevent_unlink(timer, event);
UNLOCK(&timer->lock);
#if defined(UNIT_TESTING)
usleep(100);
#endif
(void)isc_task_purgeevent(timer->task, (isc_event_t *)event);
LOCK(&timer->lock);
}

74
tests/isc/task_test.c
View File

@@ -38,6 +38,7 @@
#include <isc/util.h>
#include "netmgr/uv-compat.h"
#include "timer.c"
#include <tests/isc.h>
@@ -400,8 +401,18 @@ ISC_RUN_TEST_IMPL(privilege_drop) {
}
/*
* Basic task functions:
* Basic task variables and functions:
*/
static char one[] = "1";
static char two[] = "2";
static char three[] = "3";
static char four[] = "4";
static char tick[] = "tick";
static char tock[] = "tock";
static char quick[] = "quick";
static isc_timer_t *ti3 = NULL;
static void
basic_cb(isc_task_t *task, isc_event_t *event) {
int i, j;
@@ -434,7 +445,27 @@ basic_shutdown(isc_task_t *task, isc_event_t *event) {
}
static void
basic_tick(isc_task_t *task, isc_event_t *event) {
basic_tick1(isc_task_t *task, isc_event_t *event) {
UNUSED(task);
if (verbose) {
print_message("# %s\n", (char *)event->ev_arg);
}
/* Test for a race condition with isc_event_free() in basic_quick(). */
if (!atomic_load(&done)) {
LOCK(&lock);
if (ti3 != NULL) {
isc_timer_purge(ti3);
}
UNLOCK(&lock);
}
isc_event_free(&event);
}
static void
basic_tick2(isc_task_t *task, isc_event_t *event) {
UNUSED(task);
if (verbose) {
@@ -444,12 +475,12 @@ basic_tick(isc_task_t *task, isc_event_t *event) {
isc_event_free(&event);
}
static char one[] = "1";
static char two[] = "2";
static char three[] = "3";
static char four[] = "4";
static char tick[] = "tick";
static char tock[] = "tock";
static void
basic_quick(isc_task_t *task, isc_event_t *event) {
UNUSED(task);
isc_event_free(&event);
}
ISC_RUN_TEST_IMPL(basic) {
isc_result_t result;
@@ -466,15 +497,22 @@ ISC_RUN_TEST_IMPL(basic) {
one, two, three, four, two, three, four, NULL };
int i;
atomic_init(&done, false);
UNUSED(state);
result = isc_task_create(taskmgr, 0, &task1);
/*
* Note: running task1 and task4 on different threads, because they
* test a race condition.
*/
result = isc_task_create_bound(taskmgr, 0, &task1, 0);
assert_int_equal(result, ISC_R_SUCCESS);
result = isc_task_create(taskmgr, 0, &task2);
assert_int_equal(result, ISC_R_SUCCESS);
result = isc_task_create(taskmgr, 0, &task3);
assert_int_equal(result, ISC_R_SUCCESS);
result = isc_task_create(taskmgr, 0, &task4);
result = isc_task_create_bound(taskmgr, 0, &task4, 1);
assert_int_equal(result, ISC_R_SUCCESS);
result = isc_task_onshutdown(task1, basic_shutdown, one);
@@ -489,14 +527,21 @@ ISC_RUN_TEST_IMPL(basic) {
isc_time_settoepoch(&absolute);
isc_interval_set(&interval, 1, 0);
result = isc_timer_create(timermgr, isc_timertype_ticker, &absolute,
&interval, task1, basic_tick, tick, &ti1);
&interval, task1, basic_tick1, tick, &ti1);
assert_int_equal(result, ISC_R_SUCCESS);
ti2 = NULL;
isc_time_settoepoch(&absolute);
isc_interval_set(&interval, 1, 0);
result = isc_timer_create(timermgr, isc_timertype_ticker, &absolute,
&interval, task2, basic_tick, tock, &ti2);
&interval, task2, basic_tick2, tock, &ti2);
assert_int_equal(result, ISC_R_SUCCESS);
ti3 = NULL;
isc_time_settoepoch(&absolute);
isc_interval_set(&interval, 0, 1000);
result = isc_timer_create(timermgr, isc_timertype_ticker, &absolute,
&interval, task4, basic_quick, quick, &ti3);
assert_int_equal(result, ISC_R_SUCCESS);
sleep(2);
@@ -524,9 +569,14 @@ ISC_RUN_TEST_IMPL(basic) {
isc_task_detach(&task3);
isc_task_detach(&task4);
atomic_store(&done, true);
sleep(10);
isc_timer_destroy(&ti1);
isc_timer_destroy(&ti2);
LOCK(&lock);
isc_timer_destroy(&ti3);
UNLOCK(&lock);
}
/*