[PATCH 3/6] nptl: Make pthread_kill async-signal-safe

[Adhemerval Zanella]

On 04/12/2020 15:20, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
>> Simiar to raise (BZ #15368), pthread_kill is also defined as
>> async-signal-safe (POSIX.1-2008 TC1).  However, similar to raise
>> it has the same issues relating to signal handling.
>>
>> Different than raise, all the signal are blocked so it would be
>> possible to implement pthread_cancel (which also should be
>> async-cancel safe).
> 
> What do you mean by implementing pthread_cancel?
> 
> Patch looks okay as far as I can see, but we'll eventually need a
> different approach to deal with the TID reuse race.
> 

For TID reuse case I don't see a easy way other than add a lock
on pthread_kill with synchronizes with pthread_exit.  It would
require some changes on how we synchronize the TID clear by the
kernel.