From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Paul Menzel <pmenzel+linux-kasan-dev@molgen.mpg.de>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, stable@vger.kernel.org
Subject: Re: [PATCH] mm/kasan: Don't vfree() nonexistent vm_area.
Date: Mon, 5 Feb 2018 11:48:33 +0300 [thread overview]
Message-ID: <5ea1af5e-213d-5881-652a-c3f2c535254a@virtuozzo.com> (raw)
In-Reply-To: <20180202172027.GB16840@bombadil.infradead.org>
On 02/02/2018 08:20 PM, Matthew Wilcox wrote:
> On Thu, Feb 01, 2018 at 11:22:55PM +0300, Andrey Ryabinin wrote:
>>>> + vm = find_vm_area((void *)shadow_start);
>>>> + if (vm)
>>>> + vfree((void *)shadow_start);
>>>> + }
>>>
>>> This looks like a complicated way to spell 'is_vmalloc_addr' ...
>>>
>>
>> It's not. shadow_start is never vmalloc address.
>
> I'm confused. How can you call vfree() on something that isn't a vmalloc
> address?
>
a??vfree() is able to free any address returned by __vmalloc_node_range().
And __vmalloc_node_range() gives you any address you ask.
It doesn't have to be an address in [VMALLOC_START, VMALLOC_END] range.
That's also how the module_alloc()/module_memfree() works on architectures that
have designated area for modules.
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next prev parent reply other threads:[~2018-02-05 8:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <12c9e499-9c11-d248-6a3f-14ec8c4e07f1@molgen.mpg.de>
2018-02-01 16:33 ` [PATCH] mm/kasan: Don't vfree() nonexistent vm_area Andrey Ryabinin
2018-02-01 19:57 ` Matthew Wilcox
2018-02-01 20:22 ` Andrey Ryabinin
2018-02-02 17:20 ` Matthew Wilcox
2018-02-05 8:48 ` Andrey Ryabinin [this message]
2018-05-18 15:57 ` David Hildenbrand
2018-05-18 16:01 ` David Hildenbrand
2018-05-22 16:44 ` Andrey Ryabinin
2018-05-22 21:03 ` Andrew Morton
2018-05-23 12:33 ` Andrey Ryabinin
2018-05-26 3:31 ` [PATCH] mm-kasan-dont-vfree-nonexistent-vm_area-fix kbuild test robot
2018-05-26 3:48 ` Andrew Morton
2018-05-28 4:13 ` Ian Kent
2018-05-28 4:39 ` Ian Kent
2018-05-29 4:01 ` Ian Kent
2018-05-30 11:53 ` kbuild test robot
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