Re: [Xen-devel] [PATCH MM-PART2 RESEND v2 16/19] xen/arm: mm: Protect Xen page-table update with a spinlock

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

On 14.05.19 15:24, Julien Grall wrote:
> The function create_xen_entries() may be called concurrently. For
> instance, while the vmap allocation is protected by a spinlock, the
> mapping is not.
>
> The implementation create_xen_entries() contains quite a few TOCTOU
> races such as when allocating the 3rd-level page-tables.
>
> Thankfully, they are pretty hard to reach as page-tables are allocated
> once and never released. Yet it is possible, so we need to protect with
> a spinlock to avoid corrupting the page-tables.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
>
> ---
>      Changes in v2:
>          - Rework the commit message
> ---
Reviewed-by: Andrii Anisov <andrii_anisov@xxxxxxxx>

--
Sincerely,
Andrii Anisov.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel