Re: [PATCH] coroutine-sigaltstack: Keep SIGUSR2 handler up

[Paolo Bonzini]

On 22/01/21 22:26, Laszlo Ersek wrote:
> That seems bogus, per POSIX, given that all signals except SIGUSR2 are
> included in the mask passed to sigsuspend().

What happens if you get a SIGSTOP at exactly the wrong time?  (Yeah I 
know how incredibly unlikely that would be).

BTW if we are in a mood for cleanup, there's no reason to use 
pthread_key_t instead of __thread + qemu_thread_atexit_add (adding a 
Notifier to struct CoroutineThreadState).  That would fix the issue with 
async-signal safety of pthread_getspecific.

(It makes sense for the function not to be async-signal safe since it 
can in principle allocate memory for the data.  In practice it's most 
likely okay if the function has been called before on this thread).

Paolo