Messages in this thread | | | Date | Mon, 3 Sep 2018 15:47:51 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 2/3] x86/speculation: Apply IBPB more strictly to avoid cross-process spectre v2 leak |
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On Mon, Sep 03, 2018 at 02:45:25PM +0200, Jiri Kosina 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?
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