[RFC PATCH glibc v2] pthread_setspecific: Provide signal-safety across keys

[Florian Weimer]

* Mathieu Desnoyers:

> @@ -327,7 +328,7 @@ __nptl_deallocate_tsd (void)
>  	    {
>  	      /* The first block is allocated as part of the thread
>  		 descriptor.  */
> -	      free (level2);
> +	      (void) munmap (level2, PTHREAD_KEY_2NDLEVEL_SIZE * sizeof (*level2));
>  	      THREAD_SETMEM_NC (self, specific, cnt, NULL);

I think __nptl_deallocate_tsd needs to disable signals as well, even
when the level2 pointer is NULL, and keep them disabled until the
thread exits.  This is not a localized change; I don't know if it is
safe.