Re: [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to avoid cross-process data leak

[Jiri Kosina]

On Wed, 5 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(current, tsk, PTRACE_MODE_IBPB))
> >  			indirect_branch_prediction_barrier();
> 
> See how the new (first) argument is 'current' and you could've just used
> the old __ptrace_may_access().

Yeah, 1/3 is dropped in my current series already; this was cherry-picked 
from original Tim's series, but it is indeed superfluous.

Thanks,

-- 
Jiri Kosina
SUSE Labs