Messages in this thread Patch in this message |  | | Subject | Re: [RFC PATCH 2/2] mm: readahead: handle LARGE input to get_init_ra_size() | From | Toralf Förster <> | Date | Tue, 29 Dec 2020 19:01:55 +0100 |
| |
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)
-- Toralf
|  |