michaelh/zephyr
1
0
Fork 0
Code Releases Activity

kernel: stack: fix stack_push spinlock and return

Browse source 
The z_impl_k_stack_push() has a spinlock that is set after
stack member access, which could cause race conditions and
used multiple return statements. This commit
- moves the lock before the CHECKIF
- implements goto for flow of lock, reschedule, and unlock
- uses ret for single return at the end

Signed-off-by: Jennifer Williams <jennifer.m.williams@intel.com>
This commit is contained in:
Jennifer Williams 2020-09-29 15:16:39 -07:00 • committed by Anas Nashif
commit 4d33007486
1 changed files with 11 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

17
kernel/stack.c
View file

@ -97,14 +97,14 @@ int k_stack_cleanup(struct k_stack *stack)
int z_impl_k_stack_push(struct k_stack *stack, stack_data_t data)
{
struct k_thread *first_pending_thread;
k_spinlock_key_t key;
int ret = 0;
k_spinlock_key_t key = k_spin_lock(&stack->lock);
CHECKIF(stack->next == stack->top) {
return -ENOMEM;
ret = -ENOMEM;
goto out;
}
key = k_spin_lock(&stack->lock);
first_pending_thread = z_unpend_first_thread(&stack->wait_q);
if (first_pending_thread != NULL) {
@ -113,13 +113,18 @@ int z_impl_k_stack_push(struct k_stack *stack, stack_data_t data)
z_thread_return_value_set_with_data(first_pending_thread,
0, (void *)data);
z_reschedule(&stack->lock, key);
goto end;
} else {
*(stack->next) = data;
stack->next++;
k_spin_unlock(&stack->lock, key);
goto out;
}
return 0;
out:
k_spin_unlock(&stack->lock, key);
end:
return ret;
}
#ifdef CONFIG_USERSPACE