From: Daniel Axtens <dja@axtens.net>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org, x86@kernel.org,
glider@google.com, luto@kernel.org, linux-kernel@vger.kernel.org,
mark.rutland@arm.com, dvyukov@google.com,
christophe.leroy@c-s.fr
Cc: linuxppc-dev@lists.ozlabs.org, gor@linux.ibm.com,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v10 4/5] x86/kasan: support KASAN_VMALLOC
Date: Thu, 31 Oct 2019 00:50:05 +1100 [thread overview]
Message-ID: <87sgnamjg2.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <a144eaca-d7e1-1a18-5975-bd0bfdb9450e@virtuozzo.com>
Andrey Ryabinin <aryabinin@virtuozzo.com> writes:
> On 10/29/19 7:20 AM, Daniel Axtens wrote:
>> In the case where KASAN directly allocates memory to back vmalloc
>> space, don't map the early shadow page over it.
>>
>> We prepopulate pgds/p4ds for the range that would otherwise be empty.
>> This is required to get it synced to hardware on boot, allowing the
>> lower levels of the page tables to be filled dynamically.
>>
>> Acked-by: Dmitry Vyukov <dvyukov@google.com>
>> Signed-off-by: Daniel Axtens <dja@axtens.net>
>>
>> ---
>
>> +static void __init kasan_shallow_populate_pgds(void *start, void *end)
>> +{
>> + unsigned long addr, next;
>> + pgd_t *pgd;
>> + void *p;
>> + int nid = early_pfn_to_nid((unsigned long)start);
>
> This doesn't make sense. start is not even a pfn. With linear mapping
> we try to identify nid to have the shadow on the same node as memory. But
> in this case we don't have memory or the corresponding shadow (yet),
> we only install pgd/p4d.
> I guess we could just use NUMA_NO_NODE.
Ah wow, that's quite the clanger on my part.
There are a couple of other invocations of early_pfn_to_nid in that file
that use an address directly, but at least they reference actual memory.
I'll send a separate patch to fix those up.
> The rest looks ok, so with that fixed:
>
> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Thanks heaps! I've fixed up the nit you identifed in the first patch,
and I agree that the last patch probably isn't needed. I'll respin the
series shortly.
Regards,
Daniel
next prev parent reply other threads:[~2019-10-30 13:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-29 4:20 [PATCH v10 0/5] kasan: support backing vmalloc space with real shadow memory Daniel Axtens
2019-10-29 4:20 ` [PATCH v10 1/5] " Daniel Axtens
2019-10-29 16:42 ` Andrey Ryabinin
2019-10-30 14:29 ` Uladzislau Rezki
2019-10-31 9:36 ` Daniel Axtens
2019-10-29 4:20 ` [PATCH v10 2/5] kasan: add test for vmalloc Daniel Axtens
2019-10-29 16:43 ` Andrey Ryabinin
2019-10-29 4:20 ` [PATCH v10 3/5] fork: support VMAP_STACK with KASAN_VMALLOC Daniel Axtens
2019-10-29 17:07 ` Andrey Ryabinin
2019-10-29 4:20 ` [PATCH v10 4/5] x86/kasan: support KASAN_VMALLOC Daniel Axtens
2019-10-29 17:21 ` Andrey Ryabinin
2019-10-30 13:50 ` Daniel Axtens [this message]
2019-10-30 14:12 ` Andrey Ryabinin
2019-10-30 14:21 ` Daniel Axtens
2019-10-29 4:20 ` [PATCH v10 5/5] kasan debug: track pages allocated for vmalloc shadow Daniel Axtens
2019-10-29 17:34 ` Andrey Ryabinin
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