Re: PROBLEM: kernel crashes when running xfsdump since ~6.4

[Uladzislau Rezki <urezki@gmail.com>]

> 
> IMO, I thought we can fix this by following.
> It doesn't initialize unused variables and utilize the percpu xarray. If I said
> anything wrong, please do let me know. I can learn a lot from you all :).
> 
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 11fe5ea208aa..f9f981674b2d 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -4480,17 +4480,21 @@ void __init vmalloc_init(void)
>          */
>         vmap_area_cachep = KMEM_CACHE(vmap_area, SLAB_PANIC);
> 
> -       for_each_possible_cpu(i) {
> +       for (i = 0; i < nr_cpu_ids; i++) {
>                 struct vmap_block_queue *vbq;
>                 struct vfree_deferred *p;
> 
>                 vbq = &per_cpu(vmap_block_queue, i);
> +               xa_init(&vbq->vmap_blocks);
> +
> +               if (!cpu_possible(i))
Why do you need such check?

Thanks!

--
Uladzislau Rezki