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Date:   Wed, 5 Sep 2018 09:52:38 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Jiri Kosina <jikos@kernel.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        "Woodhouse, David" <dwmw@amazon.co.uk>,
        Oleg Nesterov <oleg@redhat.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to
 avoid cross-process data leak
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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().