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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
Date: Thu, 28 Feb 2019 19:01:54 +0100	[thread overview]
Message-ID: <20190228180154.GO32534@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190228175114.GG32494@hirez.programming.kicks-ass.net>

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?

  reply	other threads:[~2019-02-28 18:02 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-28 14:54 [PATCH 0/8] objtool: UACCESS validation v2 Peter Zijlstra
2019-02-28 14:54 ` [PATCH 1/8] kasan,x86: Frob kasan_report() in an exception Peter Zijlstra
2019-02-28 15:22   ` Dmitry Vyukov
2019-02-28 15:45     ` Peter Zijlstra
2019-02-28 15:52       ` Dmitry Vyukov
2019-02-28 16:01         ` Andrey Ryabinin
2019-02-28 16:03       ` Dmitry Vyukov
2019-02-28 17:46         ` Peter Zijlstra
2019-02-28 18:18           ` Dmitry Vyukov
2019-03-01 14:45     ` Peter Zijlstra
2019-03-01 15:06       ` Dmitry Vyukov
2019-03-01 15:23         ` Peter Zijlstra
2019-03-06 13:13           ` Peter Zijlstra
2019-03-06 13:39             ` Dmitry Vyukov
2019-03-06 13:57               ` Peter Zijlstra
2019-03-06 14:01                 ` Dmitry Vyukov
2019-03-06 14:12                   ` Peter Zijlstra
2019-03-06 14:34                     ` Peter Zijlstra
2019-03-06 14:40                       ` Dmitry Vyukov
2019-03-06 14:41                         ` Dmitry Vyukov
2019-03-06 14:55                         ` Peter Zijlstra
2019-03-06 15:01                           ` Dmitry Vyukov
2019-03-06 17:14             ` Peter Zijlstra
2019-03-06 17:27               ` Linus Torvalds
2019-03-06 17:37               ` Peter Zijlstra
2019-03-06 17:59                 ` Linus Torvalds
2019-03-07 13:49                   ` Peter Zijlstra
2019-02-28 14:54 ` [PATCH 2/8] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-02-28 14:54 ` [PATCH 3/8] objtool: Set insn->func for alternatives Peter Zijlstra
2019-02-28 14:54 ` [PATCH 4/8] objtool: Hande function aliases Peter Zijlstra
2019-02-28 14:54 ` [PATCH 5/8] objtool: Rewrite add_ignores() Peter Zijlstra
2019-02-28 14:54 ` [PATCH 6/8] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-02-28 15:10   ` Chris Wilson
2019-02-28 15:24     ` Peter Zijlstra
2019-02-28 16:49   ` Linus Torvalds
2019-02-28 17:51     ` Peter Zijlstra
2019-02-28 18:01       ` Peter Zijlstra [this message]
2019-02-28 18:29         ` Linus Torvalds
2019-02-28 19:01           ` Peter Zijlstra
2019-03-01 10:34             ` Peter Zijlstra
2019-03-01 12:27               ` Peter Zijlstra
2019-03-01 12:57                 ` Peter Zijlstra
2019-03-01 14:38                   ` Peter Zijlstra
2019-03-01 15:27                     ` Andy Lutomirski
2019-03-01 16:15                   ` Linus Torvalds
2019-03-01 16:17               ` Linus Torvalds
2019-02-28 14:54 ` [PATCH 7/8] objtool: Add UACCESS validation Peter Zijlstra
2019-02-28 14:54 ` [PATCH 8/8] objtool: Add Direction Flag validation Peter Zijlstra

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