From: Mark Rutland <mark.rutland@arm.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>,
Vegard Nossum <vegard.nossum@oracle.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Tavis Ormandy <taviso@google.com>,
Will Deacon <will.deacon@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Quentin Casasnovas <quentin.casasnovas@oracle.com>,
Kostya Serebryany <kcc@google.com>,
Eric Dumazet <edumazet@google.com>,
Alexander Potapenko <glider@google.com>,
Kees Cook <keescook@google.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Drysdale <drysdale@google.com>,
linux-arm-kernel@lists.infradead.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v2] kernel: add kcov code coverage
Date: Fri, 22 Jan 2016 12:52:11 +0000 [thread overview]
Message-ID: <20160122125210.GA10802@leverpostej> (raw)
In-Reply-To: <CACT4Y+bvReSkPa5mtb4+Uy6GsoDiuawLzfzMPoJF++1X=H06aA@mail.gmail.com>
On Fri, Jan 22, 2016 at 01:15:27PM +0100, Dmitry Vyukov wrote:
> On Fri, Jan 22, 2016 at 12:55 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> > On Mon, Jan 18, 2016 at 09:09:43PM +0100, Dmitry Vyukov wrote:
> >> On Mon, Jan 18, 2016 at 8:44 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
> >> > Regarding KASLR and dynamically loaded modules. I've looked at my
> >> > use-case and concluded
> >> > that most of the time I can work with "non-stable" PCs within a single
> >> > VM. Whenever I need to
> >> > store PCs persistently or send to another machine, I think I can
> >> > "canonicalize" PCs using
> >> > /proc/modules and /proc/kallsyms to something like (module hash,
> >> > module offset). So kernel does
> >> > not need to do this during coverage collection.
> >>
> >> On second though, maybe it's better to just always export unsigned long PCs...
> >> Need to measure how much memory coverage information consumes,
> >> and how much slower it is with uint64 PCs. Maybe I can live with large PCs,
> >> or maybe I can make syzkaller require !KASLR and compress PCs in user-space...
> >> Need to think about this more.
> >
> > I can imagine we might keep the expanded module range even in the
> > absence of full KASLR, though I don't know how realistic that thought
> > is.
>
> The last version of the patch just exposes PCs as unsigned longs
> without any compression. So it should not be a problem (at least for
> kernel, now it's user responsibility to make sense out of the PCs).
Ah, ok. Sorry for the noise!
Mark.
prev parent reply other threads:[~2016-01-22 12:52 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-13 12:48 [PATCH v2] kernel: add kcov code coverage Dmitry Vyukov
2016-01-13 22:31 ` kbuild test robot
2016-01-14 9:03 ` Kirill A. Shutemov
2016-01-14 9:10 ` Dmitry Vyukov
2016-01-14 9:23 ` Kirill A. Shutemov
2016-01-14 12:21 ` Dmitry Vyukov
2016-01-14 12:35 ` Kirill A. Shutemov
2016-01-14 12:49 ` Kirill A. Shutemov
2016-01-14 14:24 ` Dmitry Vyukov
2016-01-14 10:50 ` Andrey Ryabinin
2016-01-14 14:30 ` Dmitry Vyukov
2016-01-15 13:05 ` Andrey Ryabinin
2016-01-15 13:42 ` Will Deacon
2016-01-15 14:07 ` Dmitry Vyukov
2016-01-18 13:34 ` Andrey Ryabinin
2016-01-18 19:31 ` Dmitry Vyukov
2016-01-18 14:13 ` Mark Rutland
2016-01-18 19:44 ` Dmitry Vyukov
2016-01-18 20:09 ` Dmitry Vyukov
2016-01-22 11:55 ` Mark Rutland
2016-01-22 12:15 ` Dmitry Vyukov
2016-01-22 12:52 ` Mark Rutland [this message]
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