The incorrect sequence will cause the thread cannot be aborted in the
ISR context. The following test case failed:
tests/kernel/fatal/exception/kernel.common.stack_sentinel.
The stack sentinel detects the stack overflow as normal during a timer
ISR exit. Note that, currently, the stack overflow detection is behind
the context switch checking, and then the detection will call svc to
raise a fatal error resulting in increasing the nested counter(+1). At
this point, it needs a context switch to finally abort the thread.
However, after the fatal error handling, the program cannot do a context
switch either during the svc exit[1], or during the timer ISR exit[2].
[1] is because the svc context is in an interrupt nested state (the
nested counter is 2).
[2] is because the current point (after svc context pop out) is right
behind the switch checking.
Signed-off-by: Jaxson Han <jaxson.han@arm.com>
a7a8a64e9c