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Date:   Thu, 28 Feb 2019 19:01:54 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>, Peter Anvin <hpa@zytor.com>,
        Julien Thierry <julien.thierry@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Ingo Molnar <mingo@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        James Morse <james.morse@arm.com>, valentin.schneider@arm.com,
        Brian Gerst <brgerst@gmail.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andrew Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [PATCH 6/8] i915,uaccess: Fix redundant CLAC
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On Thu, Feb 28, 2019 at 06:51:14PM +0100, Peter Zijlstra wrote:
> On Thu, Feb 28, 2019 at 08:49:57AM -0800, Linus Torvalds wrote:
> > Yes, it is redundant (but harmlessly so) if no fault occurs.
> 
> Oooh, there's a label hidden in unsafe_put_user()...
> 
> And yes, objtool seems to miss that, damn. I'll go stare at that.

Weird, that jump is from C, not from a .fixup table. objtool _should_
see that and complain if there is a AC=1 path that reaches RET.

AFAIU validate_branch() should recurse down every single branch, right
Josh?