From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: arm64: virt_to_page() does not return right page for a kernel image address
Date: Thu, 5 Jan 2017 10:57:58 +0000 [thread overview]
Message-ID: <20170105105757.GA29765@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <322d61f1-0b72-6125-f5cd-153e0baad733@redhat.com>
On Wed, Jan 04, 2017 at 10:39:05AM -0800, Laura Abbott wrote:
> On 01/04/2017 04:13 AM, Catalin Marinas wrote:
> > On Wed, Jan 04, 2017 at 11:19:38AM +0530, Pratyush Anand wrote:
> >> I noticed that on arm64 kmap_atomic() does not return correct address
> >> corresponding to a page located in data section. It causes crash in
> >> kdump kernel with v29 kdump patches. crash happens in a newly
> >> implemented crypto test [1], and the same test fails(even though it
> >> does not crash) in 1st kernel as well.
> >>
> >> Further debugging showed that the physical address returned by
> >> virt_to_phys(kaddr) and virt_to_phys(kmap_atomic(virt_to_page(kaddr))
> >> + offset_in_page(kaddr)) are not same.
>
> I think the underlying issue has been resolved but in general, relying
> on virt_to_phys(kmap_atomic(page)) to work at all doesn't seem
> correct. On arm64 and other !CONFIG_HIGHMEM systems this currently
> returns the page_address but if it's actually remapped this isn't
> going to work.
Good point, kmap_atomic() does not always return an address in the
linear map, so virt_to_phys() on such address is not generally expected
to work (unrelated to arm64).
--
Catalin
prev parent reply other threads:[~2017-01-05 10:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-04 5:49 arm64: virt_to_page() does not return right page for a kernel image address Pratyush Anand
2017-01-04 11:11 ` Mark Rutland
2017-01-04 11:58 ` Pratyush Anand
2017-01-04 12:06 ` Mark Rutland
2017-01-04 12:23 ` Pratyush Anand
2017-01-04 13:24 ` Ard Biesheuvel
2017-01-04 14:03 ` Pratyush Anand
2017-01-04 12:13 ` Catalin Marinas
2017-01-04 18:39 ` Laura Abbott
2017-01-05 10:57 ` Catalin Marinas [this message]
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