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Re: [PATCH] Fix fail in gdb.base/interrupt-noterm.exp
- From: Pedro Alves <palves at redhat dot com>
- To: Yao Qi <qiyaoltc at gmail dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Mon, 25 Jan 2016 10:43:20 +0000
- Subject: Re: [PATCH] Fix fail in gdb.base/interrupt-noterm.exp
- Authentication-results: sourceware.org; auth=none
- References: <1453480183-5131-1-git-send-email-yao dot qi at linaro dot org> <56A25D13 dot 2080608 at redhat dot com> <86twm5r0yp dot fsf at gmail dot com> <56A26849 dot 9070206 at redhat dot com> <86powqqa57 dot fsf at gmail dot com>
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