Re: [BUG] dm-integrity: mode R resume NULL deref when DIRTY_BITMAP is set

[Yu Junzhe]

Hi Mikulas,

Thanks for the patch. We A/B-tested it on Linux 6.6.144 KASAN against the
minimized PoC (mode B format, plant SB_FLAG_DIRTY_BITMAP, load+resume
mode R).

Results:
  - unpatched: KASAN null-ptr-deref in list_get_page via
    rw_journal_sectors / dm_integrity_resume
  - with your change (skip writes in dm_integrity_resume when mode == 'R'):
    PoC completes; no list_get_page / KASAN on resume

Happy to test follow-ups if needed.

Thanks,
Yu Junzhe
FuzzAnything <fuzzanything@xxxxxxxxx>