Re: Known and unfixed active data loss bug in MM + XFS with large folios since Dec 2021 (any kernel from 6.1 upwards)

Chris Mason
2024-09-18T12:24:09Z

On 9/18/24 5:28 AM, Chris Mason wrote:
> And I attached radixcheck.py if you want to see the full script.

Since the attachment didn't actually make it through:

#!/usr/bin/env -S drgn -c vmcore

from drgn.helpers.linux.fs import *
from drgn.helpers.linux.mm import *
from drgn.helpers.linux.list import *
from drgn.helpers.linux.xarray import *
from drgn import *
import os
import sys
import time

mapping = Object(prog, 'struct address_space', address=0xffff88a22a9614e8)
#p = path_lookup(prog, sys.argv[1]);
#mapping = p.dentry.d_inode.i_mapping

for index, x in xa_for_each(mapping.i_pages.address_of_()):
if xa_is_zero(x):
continue
if xa_is_value(x):
continue

page = Object(prog, 'struct page', address=x)
folio = Object(prog, 'struct folio', address=x)

print("0x%x mapping 0x%x radix index %d page index %d flags 0x%x (%s) size %d" % (page.address_of_(), page.mapping.value_(), index, page.index, page.flags, decode_page_flags(page), folio._folio_nr_pages))