Re: [PATCH] rseq/selftests: fix parametrized test with -fpie

From: Shuah Khan
Date: Thu Sep 27 2018 - 10:04:58 EST


On 09/27/2018 07:22 AM, Steven Rostedt wrote:
> On Tue, 25 Sep 2018 13:39:36 -0400 (EDT)
> Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
>> ----- On Sep 18, 2018, at 9:53 AM, Mathieu Desnoyers mathieu.desnoyers@xxxxxxxxxxxx wrote:
>>
>>> On x86-64, the parametrized selftest code for rseq crashes with a
>>> segmentation fault when compiled with -fpie. This happens when the
>>> param_test binary is loaded at an address beyond 32-bit on x86-64.
>>>
>>> The issue is caused by use of a 32-bit register to hold the address
>>> of the loop counter variable.
>>>
>>> Fix this by using a 64-bit register to calculate the address of the
>>> loop counter variables as an offset from rip.
>>
>> Should this fix go through tip or the selftests tree ?
>>
>
> I usually have changes like this pulled through Shuah's tree with an
> ack from the maintainer of the code that it tests.
>
> -- Steve
>

Right that is what I prefer. I usually wait for an Ack. I can pull this
in.

thanks,
-- Shuah

--
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America(Silicon Valley)
shuah.kh@xxxxxxxxxxx