Re: [Qemu-devel] [PATCH] Fix signal handling of SIG_IPI when io-thread is enabled

[Blue Swirl]

Thanks, applied.

On Sat, Jul 9, 2011 at 5:33 AM, Alexandre Raymond <address@hidden> wrote:
> ping?
>
> On Wed, Jun 15, 2011 at 10:11 AM, Alexandre Raymond <address@hidden> wrote:
>> Hi Jan,
>>
>>> Why? Ahh, because of qemu_cpu_kick_self: raise(SIG_IPI)! That should
>>> generate a per-process SIG_IPI. And that may not only affect Darwin.
>>> Looks good.
>>
>> Actually, with io-thread enabled, it goes through qemu_cpu_kick_self()
>> -> qemu_cpu_kick_thread() -> pthread_kill(..., SIG_IPI).
>>
>> I think the problem is with sigwait(). It doesn't state so in the
>> Linux or Darwin man pages, but on Solaris, it says : "All signals
>> identified by the set argument must be blocked on all threads,
>> including the calling thread; otherwise, sigwait() might not work
>> correctly", which might correspond to the issue I've been witnessing
>> (ie: sigwait() unblocking once in a while on a SIGUSR1 (SIG_IPI) in
>> the event thread).
>>
>> In any case, I don't think it should attempt to catch this signal at
>> all since the cpu thread is already catching it.
>>
>> Alexandre
>>
>
>