On Mon, 6 Dec 2021 at 11:55, syzbot <syzbot+11421fbbff99b989670e@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: a51e3ac43ddb Merge tag 'net-5.16-rc4' of git://git.kernel... > git tree: net > console output: https://syzkaller.appspot.com/x/log.txt?x=17f04ebeb00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5b0eee8ab3ea1839 > dashboard link: https://syzkaller.appspot.com/bug?extid=11421fbbff99b989670e > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+11421fbbff99b989670e@xxxxxxxxxxxxxxxxxxxxxxxxx > This warning stems from mm/utils.c: /* Don't even allow crazy sizes */ if (WARN_ON_ONCE(size > INT_MAX)) return NULL; The structure that is being allocated is the page-pinning accounting. AF_XDP has an internal limit of U32_MAX pages, which is *a lot*, but still fewer than what memcg allows (PAGE_COUNTER_MAX is a LONG_MAX/PAGE_SIZE on 64b systems). The (imo hacky) workaround to silence the warning is to decrease the U32_MAX limit to something that is less than "sizeof householding struct". Note that this is a warning, and not an oops/bug. Thoughts? Björn
