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From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: Andrey Ryabinin <ryabinin.a.a@gmail•com>
Cc: Benjamin Herrenschmidt <benh@kernel•crashing.org>,
	paulus@samba•org, mpe@ellerman•id.au,
	linuxppc-dev@lists•ozlabs.org
Subject: Re: [RFC PATCH V1 0/8] KASAN ppc64 support
Date: Tue, 18 Aug 2015 14:51:06 +0530	[thread overview]
Message-ID: <87wpwtne9p.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAPAsAGz40+1+P7ANVjU0WKCsiF4=sKNEs2+Jx_gdcKpkL5nL+A@mail.gmail.com>

Andrey Ryabinin <ryabinin.a.a@gmail•com> writes:

> 2015-08-18 8:42 GMT+03:00 Aneesh Kumar K.V <aneesh.kumar@linux•vnet.ibm.com>:
>> Andrey Ryabinin <ryabinin.a.a@gmail•com> writes:
>>
>>
>> But that is introducting conditionals in core code for no real benefit.
>> This also will break when we eventually end up tracking vmalloc ?
>
> Ok, that's a very good reason to not do this.
>
> I see one potential problem in the way you use kasan_zero_page, though.
> memset/memcpy of large portions of memory ( > 8 * PAGE_SIZE) will end up
> in overflowing kasan_zero_page when we check shadow in memory_is_poisoned_n()
>

Any suggestion on how to fix that ? I guess we definitely don't want to
check for addr and size in memset/memcpy. The other option is to
do zero page mapping as is done for other architectures. That is we map
via page table a zero page. But we still have the issue of memory we
need to map the entire vmalloc range (page table memory). I was hoping to
avoid all those complexities.


-aneesh

  reply	other threads:[~2015-08-18  9:22 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-17  6:36 [RFC PATCH V1 0/8] KASAN ppc64 support Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 1/8] powerpc/mm: Add virt_to_pfn and use this instead of opencoding Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 2/8] kasan: MODULE_VADDR is not available on all archs Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 3/8] kasan: Rename kasan_enabled to kasan_report_enabled Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 4/8] kasan: Don't use kasan shadow pointer in generic functions Aneesh Kumar K.V
2015-08-17 11:36   ` Andrey Ryabinin
2015-08-18  5:29     ` Aneesh Kumar K.V
2015-08-18  9:12       ` Andrey Ryabinin
2015-08-17  6:36 ` [RFC PATCH V1 5/8] kasan: Enable arch to hook into kasan callbacks Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 6/8] kasan: Allow arch to overrride kasan shadow offsets Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 7/8] powerpc/mm: kasan: Add kasan support for ppc64 Aneesh Kumar K.V
2015-08-17 12:13   ` Andrey Ryabinin
2015-08-17 12:17     ` Andrey Ryabinin
2015-08-18  5:36       ` Aneesh Kumar K.V
2015-08-18  8:40         ` Andrey Ryabinin
2015-08-18  5:34     ` Aneesh Kumar K.V
2015-08-17  6:36 ` [RFC PATCH V1 8/8] powerpc: Disable kasan for kernel/ and mm/ directory Aneesh Kumar K.V
2015-08-17  6:54 ` [RFC PATCH V1 0/8] KASAN ppc64 support Benjamin Herrenschmidt
2015-08-17  9:50   ` Aneesh Kumar K.V
2015-08-17 10:01     ` Benjamin Herrenschmidt
2015-08-17 10:50       ` Aneesh Kumar K.V
2015-08-17 11:21         ` Benjamin Herrenschmidt
2015-08-17 11:29     ` Andrey Ryabinin
2015-08-18  5:42       ` Aneesh Kumar K.V
2015-08-18  8:50         ` Andrey Ryabinin
2015-08-18  9:21           ` Aneesh Kumar K.V [this message]
2015-08-18  9:30             ` Andrey Ryabinin

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