tests/kernel/sched/schedule_api: Fix static analysis volatile warning

We were testing the value of a volatile variable inside a zassert,
which static analysis doesn't like.  In principle, it might be
volatile because it's an MMIO register or something and the read is a
side effect, and an assertion will be optionally compiled.  (Except
here the value is just regular memory marked volatile for
threadsafety, and zassert will never be elided in a test, but the tool
doesn't know that).

Refactor a little so we always read the variable in a way the tool can
detect is consistent.

Fixes #18446

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
This commit is contained in:
Andy Ross 2019-08-19 09:06:24 -07:00 committed by Ioannis Glaropoulos
commit 28fc46ee09

View file

@ -9,7 +9,7 @@
struct k_thread user_thread;
K_SEM_DEFINE(user_sem, 0, 1);
ZTEST_BMEM volatile bool thread_was_preempt;
ZTEST_BMEM volatile int thread_was_preempt;
K_THREAD_STACK_DEFINE(ustack, STACK_SIZE);
@ -47,13 +47,27 @@ static void preempt_test_thread(void *p1, void *p2, void *p3)
void test_user_k_is_preempt(void)
{
/* thread_was_preempt is volatile, and static analysis doesn't
* like to see it being tested inside zassert_true, because
* the read is treated as a "side effect" of an assertion
* (e.g. a read is significant for things like volatile MMIO
* addresses, and assertions may or may not be compiled, even
* though here in a test they always will be and in any case
* the value is a static variable above marked volatile for
* threadsafety). Read it into a local variable first to
* evade the warning.
*/
int twp;
k_thread_create(&user_thread, ustack, STACK_SIZE, preempt_test_thread,
NULL, NULL, NULL,
k_thread_priority_get(k_current_get()),
K_USER | K_INHERIT_PERMS, 0);
k_sem_take(&user_sem, K_FOREVER);
zassert_false(thread_was_preempt, "unexpected return value");
twp = thread_was_preempt;
zassert_false(twp, "unexpected return value");
k_thread_create(&user_thread, ustack, STACK_SIZE, preempt_test_thread,
NULL, NULL, NULL,
@ -61,7 +75,8 @@ void test_user_k_is_preempt(void)
K_USER | K_INHERIT_PERMS, 0);
k_sem_take(&user_sem, K_FOREVER);
zassert_true(thread_was_preempt, "unexpected return value");
twp = thread_was_preempt;
zassert_true(twp, "unexpected return value");
}