Re: [PATCH] Fix fail in gdb.base/interrupt-noterm.exp

Pedro Alves
2016-01-25T10:43:25Z

On 01/25/2016 09:30 AM, Yao Qi wrote:
> Pedro Alves <palves@redhat.com> writes:
>
>> If 1. is followed by 3., then the \\003 is always read by gdb
>
> s/ready by/sent by/ ?

I meant, s/by gdb/by gdbserver/.

>>
>> It still seems to me like a gdbserver bug.
>>
>> I think that after calling enable_async_io, we need to check whether
>> input is already pending from GDB, and if so, process it immediately -- we
>> know the only input coming from GDB at this point is a \\003. IOW, I think
>> we need to call input_interrupt after calling enable_async_io. input_interrupt
>> already uses select before reading, so it handles the case of there
>> being no input available without blocking.
>>
>> However, we need to be careful, because a SIGIO can race with calling
>> input_interrupt from mainline code...
>
> What you mean here is that we can call input_interrupt after calling
> enable_async_io, but meanwhile, \\0003 arrives, and input_interrupt is
> invoked as a SIGIO handler, so there is a race. Is it correct?

That's correct.

>
> I agree your next email about the approach of block/unblock SIGIO is
> better. I'll give a fix that way.
>

Great, thanks!

--
Pedro Alves