Re: [PATCH memcg v6] net: set proper memcg for net_init hooks allocations

[Shakeel Butt]

On Mon, Jun 6, 2022 at 11:45 AM Vasily Averin <vvs@xxxxxxxxxx> wrote:
>
[...]
>
> As far as I understand this report means that 'init_net' have incorrect
> virtual address on arm64.

So, the two call stacks tell the addresses belong to the kernel
modules (nfnetlink and nf_tables) whose underlying memory is allocated
through vmalloc and virt_to_page() does not work on vmalloc()
addresses.

>
> Roman, Shakeel, I need your help
>
> Should we perhaps verify kaddr via virt_addr_valid() before using virt_to_page()
> If so, where it should be checked?

I think virt_addr_valid() check in mem_cgroup_from_obj() should work
but I think it is expensive on the arm64 platform. The cheaper and a
bit hacky way to avoid such addresses is to directly use
is_vmalloc_addr() directly.