From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Alexander Potapenko <glider@google.com>,
adech.fo@gmail.com, cl@linux.com, dvyukov@google.com,
akpm@linux-foundation.org, rostedt@goodmis.org,
iamjoonsoo.kim@lge.com, js1304@gmail.com, kcc@google.com
Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm, kasan: introduce a special shadow value for allocator metadata
Date: Tue, 31 May 2016 14:52:49 +0300 [thread overview]
Message-ID: <574D7B11.8090709@virtuozzo.com> (raw)
In-Reply-To: <1464691466-59010-1-git-send-email-glider@google.com>
On 05/31/2016 01:44 PM, Alexander Potapenko wrote:
> Add a special shadow value to distinguish accesses to KASAN-specific
> allocator metadata.
>
> Unlike AddressSanitizer in the userspace, KASAN lets the kernel proceed
> after a memory error. However a write to the kmalloc metadata may cause
> memory corruptions that will make the tool itself unreliable and induce
> crashes later on. Warning about such corruptions will ease the
> debugging.
It will not. Whether out-of-bounds hits metadata or not is absolutely irrelevant
to the bug itself. This information doesn't help to understand, analyze or fix the bug.
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WARNING: multiple messages have this Message-ID (diff)
From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Alexander Potapenko <glider@google.com>, <adech.fo@gmail.com>,
<cl@linux.com>, <dvyukov@google.com>, <akpm@linux-foundation.org>,
<rostedt@goodmis.org>, <iamjoonsoo.kim@lge.com>,
<js1304@gmail.com>, <kcc@google.com>
Cc: <kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm, kasan: introduce a special shadow value for allocator metadata
Date: Tue, 31 May 2016 14:52:49 +0300 [thread overview]
Message-ID: <574D7B11.8090709@virtuozzo.com> (raw)
In-Reply-To: <1464691466-59010-1-git-send-email-glider@google.com>
On 05/31/2016 01:44 PM, Alexander Potapenko wrote:
> Add a special shadow value to distinguish accesses to KASAN-specific
> allocator metadata.
>
> Unlike AddressSanitizer in the userspace, KASAN lets the kernel proceed
> after a memory error. However a write to the kmalloc metadata may cause
> memory corruptions that will make the tool itself unreliable and induce
> crashes later on. Warning about such corruptions will ease the
> debugging.
It will not. Whether out-of-bounds hits metadata or not is absolutely irrelevant
to the bug itself. This information doesn't help to understand, analyze or fix the bug.
next prev parent reply other threads:[~2016-05-31 11:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 10:44 [PATCH] mm, kasan: introduce a special shadow value for allocator metadata Alexander Potapenko
2016-05-31 10:44 ` Alexander Potapenko
2016-05-31 11:52 ` Andrey Ryabinin [this message]
2016-05-31 11:52 ` Andrey Ryabinin
2016-05-31 17:49 ` Alexander Potapenko
2016-05-31 17:49 ` Alexander Potapenko
2016-06-01 15:23 ` Andrey Ryabinin
2016-06-01 15:23 ` Andrey Ryabinin
2016-06-01 16:31 ` Alexander Potapenko
2016-06-01 16:31 ` Alexander Potapenko
2016-06-02 12:02 ` Alexander Potapenko
2016-06-02 12:02 ` Alexander Potapenko
2016-06-02 12:17 ` Andrey Ryabinin
2016-06-02 12:17 ` Andrey Ryabinin
2016-06-02 12:18 ` Alexander Potapenko
2016-06-02 12:18 ` Alexander Potapenko
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