Re: [PATCH 2/8] gdbserver: Add thread parameter to linux_get_auxv and linux_get_hwcap

[Thiago Jung Bauermann <thiago.bauermann@linaro.org>]

Hello Luis,

Thank you for your review.

Luis Machado <luis.machado@arm.com> writes:

> On 9/8/22 07:41, Thiago Jung Bauermann via Gdb-patches wrote:
>> This patch doesn't change gdbserver behaviour, but after later changes are
>> made it avoids a null pointer dereference when HWCAP needs to be obtained
>> for a specific process while current_thread is nullptr.
>> Fixing linux_read_auxv, linux_get_hwcap and linux_get_hwcap2 to take a
>> thread_info parameter seems more correct than setting current_thread in one
>> particular code path.
>> Changes are propagated to allow passing the thread parameter through the
>> call chain.
>
> I suppose the effects will only be known when later patches are
> applied. But the auxv data is per-process, right?

AFAIK yes.

> It sounds a bit strange to pass a thread for the hwcap/auxv lookup. Is
> there some other reason to do that?

Good point. I did it this way without thinking about it because the
read_auxv methods use current_thread. I changed the patch to add an
“int pid” parameter instead and it worked fine. I still get the PID
from current_thread when it's not available from the calling function
though.

-- 
Thiago