Re: [tip:x86/vdso] x86/vdso32/syscall.S: Do not load __USER32_DS to %ss

Andy Lutomirski
2015-04-23T16:50:41Z

On Thu, Apr 23, 2015 at 9:41 AM, Denys Vlasenko
<vda.linux@googlemail.com> wrote:
> An alternative fix would be, if we decided to schedule
> in an interrupt, check %ss for zero and reload it
> with __KERNEL_DS before schedule.

For anyone who has the right hardware (not me!), a possible reproducer is here:

https://git.kernel.org/cgit/linux/kernel/git/luto/misc-tests.git/

make && taskset -c 0 ./sysret_ss_attrs_32

--Andy

--
Andy Lutomirski
AMA Capital Management, LLC