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

On Tue, 25 Sep 2018 13:39:36 -0400 (EDT)
Mathieu Desnoyers [off-list ref] wrote:

----- On Sep 18, 2018, at 9:53 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:

quoted

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