vfs_aio.c is still not safe

[David Xu]

David Xu wrote:

> If a user process got a signal which will bring it down, thread_single()
> call in exit1() should cause the kthreads to exit, this can be done.
> This also reminds me another problem, if all user threads exited by
> calling e.g: thr_exit or kse_exit, now, these kthreads should exit too,
> so the code should be adjusted,not only ptrace code.
> 
> 

I have rechecked thr_exit(), there is a band-aid, the lastest thread can
not exit via thr_exit(), so thr_exit and kse_exit need not be worried.