Re: [PATCH v7 0/2] badblocks: fix rounding bug and validate input range

Hi Jens, Coly,

Gentle ping on this series. Patch 1/2 has Coly's Reviewed-by, and
both patches address:

- an RCU stall / kernel hang reachable via the nvdimm ioctl path
  (badblocks_check() looping with a non-advancing cursor)
- a 32-bit (arm/i386) build break from 64-bit division helpers,
  reported by the kernel test robot

Both are tagged Fixes: and Cc: stable, so happy to resend or rebase
if anything's needed on my end  just let me know.

Thanks,
Ramesh

On Tue, Jul 21, 2026 at 10:11=E2=80=AFPM Ramesh Adhikari
<[email protected]> wrote:
>
> Two related fixes to block/badblocks.c:
>
> Patch 1/2 fixes the actual reported bug: round_up()/round_down() don't
> modify their argument in place, they return the rounded value, and the
> callers in _badblocks_set()/_badblocks_clear()/badblocks_check() were
> discarding that return value. Depending on caller alignment this could
> leave sectors unrounded or, in the reported case, stall the CPU with a
> non-advancing cursor when reached via the nvdimm ioctl path. It also
> fixes a 32-bit build breakage reported by kernel test robot, since the
> old rounddown()/roundup() macros pull in 64-bit division helpers not
> linked on 32-bit builds. Unchanged since v6.
>
> Patch 2/2 hardens the same three functions against the input-range and
> shift edge cases the round_up/round_down fix exposed: s + sectors
> overflow, and rounding itself wrapping past ULLONG_MAX. Revised in v7
> per Coly's review of v6 =E2=80=94 see the changelog in that patch for det=
ails.
> The remaining open item, bounding bb->shift where it's populated from
> the on-disk MD superblock in drivers/md/md.c, is being sent separately
> since it's a different file and a different root cause (missing input
> validation, not a rounding bug).
>
> Ramesh Adhikari (2):
>   badblocks: fix in-place round_up/round_down usage bug
>   badblocks: validate sector range and shift before rounding
>
>  block/badblocks.c         | 40 ++++++++++++++++++++++++++++++++-------
>  include/linux/badblocks.h |  6 +++++-
>  2 files changed, 38 insertions(+), 8 deletions(-)
>
> --
> 2.43.0
>