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Subject: Re: [PATCH 1/2] mm/mprotect: Call arch_validate_prot under mmap_lock
 and with length
To: Catalin Marinas <catalin.marinas@arm.com>
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From: Khalid Aziz <khalid.aziz@oracle.com>
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Cc: Jann Horn <jannh@google.com>, linuxppc-dev@lists.ozlabs.org,
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On 10/15/20 3:05 AM, Catalin Marinas wrote:
> On Wed, Oct 14, 2020 at 03:21:16PM -0600, Khalid Aziz wrote:
>> What FreeBSD does seems like a reasonable thing to do. Any way first
>> thing to do is to update sparc to use arch_validate_flags() and update=

>> sparc_validate_prot() to not peek into vma without lock.
>=20
> If you go for arch_validate_flags(), I think sparc_validate_prot()
> doesn't need the vma at all.

Yes, the plan is to move vma flag check from sparc_validate_prot() to
arch_validate_flags()..

>=20
> BTW, on the ADI topic, I think you have a race in do_swap_page() since
> set_pte_at() is called before arch_do_swap_page(). So a thread in the
> same process would see the new mapping but the tags have not been
> updated yet. Unless sparc relies on the new user pte to be set, I think=

> you can just swap the two calls.
>=20

Thanks for pointing that out. I will take a look at it.

--
Khalid