On 12/29/20 10:01 AM, Toralf Förster wrote:
> On 12/23/20 2:50 AM, Randy Dunlap wrote:
>>> What motivates this change? Is there any reason to think this can
>>> happen?
>> Spotted in the wild:
> I run 2 hardened Gentoo systems, a server and a desktop.
>
> I patched the server with this:
>
> mr-fox ~ # cat ubsan.patch
> --- linux-5.10.1.orig/mm/readahead.c
> +++ linux-5.10.1/mm/readahead.c
> @@ -310,7 +310,11 @@ void force_page_cache_ra(struct readahea
> */
> static unsigned long get_init_ra_size(unsigned long size, unsigned
> long max)
> {
> - unsigned long newsize = roundup_pow_of_two(size);
> + unsigned long newsize;
> +
> + if (!size)
> + size = 32;
> + newsize = roundup_pow_of_two(size);
>
> if (newsize <= max / 32)
> newsize = newsize * 4;
>
>
>
> and the issue did no longer occurred at the server (5.10.2).
>
> I did not patched the desktop system and the issue occurred still 3
> times since 21th of december (5.10.2/3)
Yes, that's the patch that I posted on 2020-DEC-22.
Looks like I should submit a real patch for that.
thanks.
--
~Randy
