Re: GDB 8.1 release -- 2018-01-08 update

[Pedro Alves <palves@redhat.com>]

On 01/08/2018 09:54 AM, Maciej W. Rozycki wrote:
> Hi Joel,
> 
>>   * [Maciej] remote/22597
>>     Empty `qsThreadInfo' reply handling regression causing inability to execute
>>
>>     I'm trying to understand whether this is specific to mips or more
>>     general. And whether this only affects GDB when debugging with older
>>     stubs or whether it affects us more generally.
>>
>>     Depending on the answer, the issue might not be so severe as
>>     to hold the release.
>>
>>     Maciej - can you tell where we are on this issue, and whether
>>     you think it really is blocking for 8.1?
> 
>  GDB uses the special thread ID 0, standing for `any', which older 
> `gdbserver' versions do not recognise.  It does not verify beforehand 
> whether `gdbserver' supports this request and does not handle an error 
> reply gracefully.  Consequently an error reply to a `Hg0' packet issued 
> causes GDB to lose track of what is going on, making it impossible to 
> continue with the debug session.  This happens with all sessions in the 
> initial connection handshake, making the combination of new GDB and old 
> `gdbserver' unusable.

I'm looking at this.  I can reproduce it on x86-64 using a gdbserver
from 2007 (git hash "f8b73d13b7ca^", the same revision Maciej's
gdbserver is built from).  I confirm that 5cd63fda035d somehow
introduces the regression.  No idea why yet.

So not specific to MIPS.

Thanks,
Pedro Alves