From: Pedro Alves <palves@redhat.com>
To: Yao Qi <qiyaoltc@gmail.com>
Cc: gdb-patches@sourceware.org
Subject: Re: [PATCH] Fix fail in gdb.base/interrupt-noterm.exp
Date: Mon, 25 Jan 2016 10:43:00 -0000 [thread overview]
Message-ID: <56A5FC48.70608@redhat.com> (raw)
In-Reply-To: <86powqqa57.fsf@gmail.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
next prev parent reply other threads:[~2016-01-25 10:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 16:29 Yao Qi
2016-01-22 16:47 ` Pedro Alves
2016-01-22 17:14 ` Yao Qi
2016-01-22 17:35 ` Pedro Alves
2016-01-22 18:30 ` Pedro Alves
2016-01-25 9:30 ` Yao Qi
2016-01-25 10:43 ` Pedro Alves [this message]
2016-01-26 9:59 ` [PATCH 0/2 V2] Fix a " Yao Qi
2016-01-26 9:59 ` [PATCH 2/2] [GDBserver] Block and unblock SIGIO Yao Qi
2016-01-26 12:01 ` Pedro Alves
2016-01-26 13:55 ` Yao Qi
2016-01-26 9:59 ` [PATCH 1/2] [GDBserver] Check input interrupt after reading in a packet Yao Qi
2016-01-26 11:42 ` Pedro Alves
2016-01-26 13:53 ` Yao Qi
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