Re: [PATCH] ptrace: add ability to retrieve signals without removing them from a queue

[Pedro Alves <palves@redhat.com>]

On 02/15/2013 07:43 PM, Oleg Nesterov wrote:
> On 02/15, Pedro Alves wrote:
>>
>> Not sure I'm reading the patch right, but it looks like GDB would
>> be able to use this as alternative to PTRACE_GET_SIGINFO variant
> 
> No, it is different. PTRACE_GETSIGINFO reports the siginfo for the signal
> which was already dequeued (ignoring the fact ->last_siginfo != NULL doesn't
> necessarily mean we report a signal), while this patch allows to look at
> the pending signals which were not reported yet.

Ah, I had assumed queue position 0 would be the dequeued signal.

>> I wouldn't mind if this was added unconditionally
>> instead of wrapped on CONFIG_CHECKPOINT_RESTORE.
> 
> I agree. If you think gdb can use this new feature,  CONFIG_ can go away.

I think so -- we can add a gdb command to dump the list of
pending signals, which I think is something that'd be useful.

> 
>> We'd miss the poke
>> variant, but that looks like something that could be always be added
>> later.
> 
> Yes. _POKE_ or _QUEUE_ or _DEQUEUE_, we can add more features if user-
> space wants them.

-- 
Pedro Alves