linux-kernel - Re: zram corruption due to uninitialized do_swap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <CABWYdi1zbc5pN28AKA31cGkD---7ODAOKQ7Tp=d=jhYScHDNFw@mail.gmail.com>
Date:   Mon, 14 Mar 2022 21:54:06 -0700
From:   Ivan Babrou <ivan@...udflare.com>
To:     Hillf Danton <hdanton@...a.com>
Cc:     Minchan Kim <minchan@...nel.org>, Linux MM <linux-mm@...ck.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: zram corruption due to uninitialized do_swap_page fault

On Mon, Mar 14, 2022 at 9:34 PM Hillf Danton <hdanton@...a.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.