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

[Peter Zijlstra]

On Tue, Sep 04, 2018 at 04:42:02PM +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(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().