lkml.org 
[lkml]   [2018]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 2/3] x86/speculation: Apply IBPB more strictly to avoid cross-process spectre v2 leak
On Mon, 3 Sep 2018, Peter Zijlstra wrote:

> > if (tsk && tsk->mm &&
> > tsk->mm->context.ctx_id != last_ctx_id &&
> > - get_dumpable(tsk->mm) != SUID_DUMP_USER)
> > + ___ptrace_may_access(tsk, current, PTRACE_MODE_IBPB))
> > indirect_branch_prediction_barrier();
>
> So the question posed here is: can @next ptrace @prev?
>
> Which confuses me greatly; it is @prev doing the BTB poisoning for
> @next, so we want to know if @prev can ptrace @next, no?

Good catch, it's the other way around, thanks.

I'll wait for more review and send eventually v3 properly threaded (sorry
for that as well ... not the best monday I've had today).

--
Jiri Kosina
SUSE Labs

\
 
 \ /
  Last update: 2018-09-03 15:58    [W:0.039 / U:1.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site