Re: zram corruption due to uninitialized do_swap_page fault

[Ivan Babrou <ivan@cloudflare.com>]

On Mon, Mar 14, 2022 at 9:34 PM Hillf Danton <hdanton@sina.com> wrote:
> Can you test if the race comes from the diff below wrt zram_free_page?
>
> Hillf
>
> --- upstream/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -392,11 +392,6 @@ int swap_readpage(struct page *page, boo
>         if (sis->flags & SWP_SYNCHRONOUS_IO) {
>                 ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
>                 if (!ret) {
> -                       if (trylock_page(page)) {
> -                               swap_slot_free_notify(page);
> -                               unlock_page(page);
> -                       }
> -
>                         count_vm_event(PSWPIN);
>                         goto out;
>                 }

I tried it without the previous patch (the one commenting out
swap_slot_free_notify in end_swap_bio_read) and it still fails.