Re: [PATCH v6 17/20] mm/mmap: Use vms accounted pages in mmap_region()
From: Paul Moore
Date: Wed Aug 21 2024 - 12:35:39 EST
On Tue, Aug 20, 2024 at 8:02 PM Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> wrote:
>
> From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
>
> Change from nr_pages variable to vms.nr_accounted for the charged pages
> calculation. This is necessary for a future patch.
>
> This also avoids checking security_vm_enough_memory_mm() if the amount
> of memory won't change.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> Cc: Kees Cook <kees@xxxxxxxxxx>
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Reviewed-by: Kees Cook <kees@xxxxxxxxxx>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> ---
> mm/mmap.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
I'm pretty sure I already ACK'd this, but I don't see it above so here
it is again:
Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx> (LSM)
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 19dac138f913..2a4f1df96f94 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1413,9 +1413,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> */
> if (accountable_mapping(file, vm_flags)) {
> charged = pglen;
> - charged -= nr_accounted;
> - if (security_vm_enough_memory_mm(mm, charged))
> + charged -= vms.nr_accounted;
> + if (charged && security_vm_enough_memory_mm(mm, charged))
> goto abort_munmap;
> +
> vms.nr_accounted = 0;
> vm_flags |= VM_ACCOUNT;
> }
> --
> 2.43.0
--
paul-moore.com