From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Greg Hackmann <ghackmann@google.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Michal Marek <mmarek@suse.com>
Cc: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, linux-kbuild@vger.kernel.org,
Matthias Kaehlcke <mka@chromium.org>,
Michael Davidson <md@google.com>
Subject: Re: [PATCH 2/4] kasan: added functions for unpoisoning stack variables
Date: Mon, 10 Jul 2017 13:31:05 +0300 [thread overview]
Message-ID: <d3f1ab84-3fe2-f4ea-5481-82bc63b9d09c@virtuozzo.com> (raw)
In-Reply-To: <20170706220114.142438-3-ghackmann@google.com>
On 07/07/2017 01:01 AM, Greg Hackmann wrote:
> From: Alexander Potapenko <glider@google.com>
>
> As a code-size optimization, LLVM builds since r279383 may
> bulk-manipulate the shadow region when (un)poisoning large memory
> blocks. This requires new callbacks that simply do an uninstrumented
> memset().
>
> This fixes linking the Clang-built kernel when using KASAN.
>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> [ghackmann@google.com: fix memset() parameters, and tweak
> commit message to describe new callbacks]
> Signed-off-by: Greg Hackmann <ghackmann@google.com>
> ---
> mm/kasan/kasan.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
> index 892b626f564b..89911e5c69f9 100644
> --- a/mm/kasan/kasan.c
> +++ b/mm/kasan/kasan.c
> @@ -828,6 +828,21 @@ void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
> }
> EXPORT_SYMBOL(__asan_allocas_unpoison);
>
> +/* Emitted by the compiler to [un]poison local variables. */
> +#define DEFINE_ASAN_SET_SHADOW(byte) \
> + void __asan_set_shadow_##byte(const void *addr, size_t size) \
> + { \
> + __memset((void *)addr, 0x##byte, size); \
> + } \
> + EXPORT_SYMBOL(__asan_set_shadow_##byte)
> +
> +DEFINE_ASAN_SET_SHADOW(00);
> +DEFINE_ASAN_SET_SHADOW(f1);
> +DEFINE_ASAN_SET_SHADOW(f2);
> +DEFINE_ASAN_SET_SHADOW(f3);
> +DEFINE_ASAN_SET_SHADOW(f5);
> +DEFINE_ASAN_SET_SHADOW(f8);
I think we can remove f8 as it should be used only by use-after-return instrumentation.
We don't use it in the kernel
> +
> #ifdef CONFIG_MEMORY_HOTPLUG
> static int kasan_mem_notifier(struct notifier_block *nb,
> unsigned long action, void *data)
>
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next prev parent reply other threads:[~2017-07-10 10:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-06 22:01 [PATCH 0/4] kasan: add clang support Greg Hackmann
2017-07-06 22:01 ` [PATCH 1/4] kasan: support alloca() poisoning Greg Hackmann
2017-07-07 0:09 ` Greg Hackmann
2017-07-10 8:44 ` Dmitry Vyukov
2017-07-13 22:40 ` Greg Hackmann
2017-07-14 6:13 ` Dmitry Vyukov
2017-07-10 10:30 ` Andrey Ryabinin
2017-07-13 22:49 ` Greg Hackmann
2017-07-14 16:52 ` Andrey Ryabinin
2017-07-06 22:01 ` [PATCH 2/4] kasan: added functions for unpoisoning stack variables Greg Hackmann
2017-07-10 8:46 ` Dmitry Vyukov
2017-07-10 10:31 ` Andrey Ryabinin [this message]
2017-07-06 22:01 ` [PATCH 3/4] kasan: support LLVM-style asan parameters Greg Hackmann
2017-07-10 8:47 ` Dmitry Vyukov
2017-07-06 22:01 ` [PATCH 4/4] kasan: add compiler support for clang Greg Hackmann
2017-07-10 8:48 ` Dmitry Vyukov
2017-07-10 10:34 ` Andrey Ryabinin
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