CooCox CoOS User's Guide

4.3 Stack Overflow Check
Stack Overflow refers to that the size of the stack used when a task is
running exceeds the size that assigned to the task, which results in writing data
to the memory outside the stack. This may lead to the coverage of the system
or other tasks’ data as well as the exception of memory access. The stack size
assigned to each task is fixed in multi-tasking kernel. Once the stack overflow
is not handled when the system is running, it may lead to system crashes.
When creating a task in CooCox CoOS, the system will save the stack
bottom address in the task control block and write a special value into the
memory block of the stack bottom address in order to judge whether the stack
overflows. CooCox CoOS will check whether there is a stack overflow during
each task scheduling.
Code 8 Stack overflow inspection
if((pCurTcb->stkPtr < pCurTcb->stack)||(*(U32*)(pCurTcb->stack) != MAGIC_WORD))
{
CoStkOverflowHook(pCurTcb->taskID); /* Yes,call hander */
}
When stack overflow in a task, the system will call CoStkOverflowHook
(taskID) automatically. You can add the handling of stack overflow in the
function. The parameter of this function is the ID of the task which has stack
overflow.
Code 9 The handling function of stack overflow
void CoStkOverflowHook(OS_TID taskID)
{
/* Process stack overflow in here */
for(; ;)
{
…
}
}
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