From: Catalin Marinas <catalin.marinas@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Marco Elver <elver@google.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Walter Wu <walter-zh.wu@mediatek.com>,
Elena Petrova <lenaptr@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>
Subject: Re: [PATCH 2/4] kasan, arm64: don't instrument functions that enable kasan
Date: Fri, 31 Jul 2020 15:21:27 +0100 [thread overview]
Message-ID: <20200731142126.GE29569@gaia> (raw)
In-Reply-To: <55d432671a92e931ab8234b03dc36b14d4c21bfb.1596199677.git.andreyknvl@google.com>
On Fri, Jul 31, 2020 at 03:20:39PM +0200, Andrey Konovalov wrote:
> This patch prepares Software Tag-Based KASAN for stack tagging support.
>
> With stack tagging enabled, KASAN tags stack variable in each function
> in its prologue. In start_kernel() stack variables get tagged before KASAN
> is enabled via setup_arch()->kasan_init(). As the result the tags for
> start_kernel()'s stack variables end up in the temporary shadow memory.
> Later when KASAN gets enabled, switched to normal shadow, and starts
> checking tags, this leads to false-positive reports, as proper tags are
> missing in normal shadow.
>
> Disable KASAN instrumentation for start_kernel(). Also disable it for
> arm64's setup_arch() as a precaution (it doesn't have any stack variables
> right now).
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
For arm64:
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
next prev parent reply other threads:[~2020-07-31 14:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 13:20 [PATCH 0/4] kasan: support stack instrumentation for tag-based mode Andrey Konovalov
2020-07-31 13:20 ` [PATCH 1/4] kasan: don't tag stacks allocated with pagealloc Andrey Konovalov
2020-07-31 13:20 ` [PATCH 2/4] kasan, arm64: don't instrument functions that enable kasan Andrey Konovalov
2020-07-31 14:21 ` Catalin Marinas [this message]
2020-07-31 13:20 ` [PATCH 3/4] kasan: allow enabling stack tagging for tag-based mode Andrey Konovalov
2020-07-31 13:20 ` [PATCH 4/4] kasan: adjust kasan_stack_oob " Andrey Konovalov
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