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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Peter Zijlstra <peterz@infradead.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>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH 5/6] objtool: Add UACCESS validation
Date: Wed, 27 Feb 2019 08:18:21 -0800	[thread overview]
Message-ID: <CAHk-=wg6P=hDhq+kPs0TCCvN7_q3usW5WNWzfdCBcLX_syoVxg@mail.gmail.com> (raw)
In-Reply-To: <20190227140830.GP32494@hirez.programming.kicks-ass.net>

On Wed, Feb 27, 2019 at 6:08 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> So KASAN is wildly unhappy..

Yeah, well, with KASAN you definitely end up doing lots and lots for
calls for just regular memory accesses.

Which we obviously need to do for most uaccess cases.

I think you should just say "ok, kasan reporting will possibly run with AC on".

Again, having AC on isn't fatal. It just makes the window where you
can incorrectly access user space through a wild pointer bigger.

So the whole "run with AC on" thing isn't a big deal, apart from the
scheduling case.

And we know how to fix the scheduling case by just doing the
save/restore thing..

                   Linus

  parent reply	other threads:[~2019-02-27 16:26 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-25 12:43 [PATCH 0/6] objtool: UACCESS validation Peter Zijlstra
2019-02-25 12:43 ` [PATCH 1/6] x86/uaccess: Dont evaluate argument inside AC region Peter Zijlstra
2019-02-25 15:43   ` Andy Lutomirski
2019-02-25 16:02     ` Peter Zijlstra
2019-02-25 16:36     ` Borislav Petkov
2019-02-25 16:50       ` Andy Lutomirski
2019-02-25 19:09     ` Linus Torvalds
2019-02-25 19:18       ` Borislav Petkov
2019-02-25 18:10   ` [tip:x86/urgent] x86/uaccess: Don't leak the AC flag into __put_user() value evaluation tip-bot for Andy Lutomirski
2019-02-25 19:46   ` tip-bot for Andy Lutomirski
2019-02-25 12:43 ` [PATCH 2/6] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-02-25 15:41   ` Andy Lutomirski
2019-02-25 16:10     ` Peter Zijlstra
2019-02-25 16:29       ` Andy Lutomirski
2019-02-25 16:37         ` Peter Zijlstra
2019-02-25 16:41           ` Peter Zijlstra
2019-02-25 16:49           ` Andy Lutomirski
2019-02-25 12:43 ` [PATCH 3/6] objtool: Set insn->func for alternatives Peter Zijlstra
2019-02-25 12:43 ` [PATCH 4/6] objtool: Replace STACK_FRAME_NON_STANDARD annotation Peter Zijlstra
2019-02-25 16:11   ` Josh Poimboeuf
2019-02-25 16:17     ` Peter Zijlstra
2019-02-25 16:23       ` Josh Poimboeuf
2019-02-27 12:20     ` Peter Zijlstra
2019-02-28  0:30       ` Andy Lutomirski
2019-02-25 12:43 ` [PATCH 5/6] objtool: Add UACCESS validation Peter Zijlstra
2019-02-25 15:53   ` Andy Lutomirski
2019-02-25 16:12     ` Peter Zijlstra
2019-02-25 17:15       ` Peter Zijlstra
2019-02-25 17:34         ` Linus Torvalds
2019-02-25 17:38         ` Josh Poimboeuf
2019-02-27 14:08   ` Peter Zijlstra
2019-02-27 14:17     ` Andrey Ryabinin
2019-02-27 14:26       ` Peter Zijlstra
2019-02-27 14:33         ` Peter Zijlstra
2019-02-27 15:40           ` Dmitry Vyukov
2019-02-27 17:28             ` Peter Zijlstra
2019-02-28  9:40               ` Peter Zijlstra
2019-02-28  9:59                 ` Dmitry Vyukov
2019-02-28 10:05                   ` Dmitry Vyukov
2019-02-28 10:52                     ` Peter Zijlstra
2019-02-27 16:18     ` Linus Torvalds [this message]
2019-02-27 17:30       ` Peter Zijlstra
2019-02-27 17:36         ` Linus Torvalds
2019-02-25 12:43 ` [PATCH 6/6] objtool: Add Direction Flag validation Peter Zijlstra

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