kern/33951: pthread_cancel is ignored

[David Xu]

Daniel Eischen wrote:

>>I had enabled asynchornous cancelling for M:N thread in libkse but not 
>>1:1 thread,
>>simplest way to support asynchronous cancelling for 1:1 is to use 
>>signal, but it will
>>occupy a signal like Linux's SIGUSR1, another way is to use upcall,  
>>but  it is
>>slight complicated.
>>    
>>
>
>An upcall would be nice since it wouldn' use a signal.  It could
>be treated like a signal where you push it on the thread's stack
>but use the upcall function instead of a signal handling function.
>
>  
>
I am working on it,  hope I can work out a patch in next days.