linux-kernel - Re: [PATCH 1/2] mm: provide a sane PTE walking API for modules

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210205134927.GL4718@ziepe.ca>
Date:   Fri, 5 Feb 2021 09:49:27 -0400
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        dan.j.williams@...el.com
Subject: Re: [PATCH 1/2] mm: provide a sane PTE walking API for modules

On Fri, Feb 05, 2021 at 05:32:58AM -0500, Paolo Bonzini wrote:
> Currently, the follow_pfn function is exported for modules but
> follow_pte is not.  However, follow_pfn is very easy to misuse,
> because it does not provide protections (so most of its callers
> assume the page is writable!) and because it returns after having
> already unlocked the page table lock.
> 
> Provide instead a simplified version of follow_pte that does
> not have the pmdpp and range arguments.  The older version
> survives as follow_invalidate_pte() for use by fs/dax.c.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---
>  arch/s390/pci/pci_mmio.c |  2 +-
>  fs/dax.c                 |  5 +++--
>  include/linux/mm.h       |  6 ++++--
>  mm/memory.c              | 35 ++++++++++++++++++++++++++++++-----
>  4 files changed, 38 insertions(+), 10 deletions(-)

Looks good to me, thanks

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Jason