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

Hi Ramesh,

I will review the 2nd patch soon.

Thanks.

Coly Li

> 2026=E5=B9=B48=E6=9C=884=E6=97=A5 13:41=EF=BC=8CRamesh Adhikari <adhikari=
[email protected]> =E5=86=99=E9=81=93=EF=BC=9A
>=20
> Hi Jens, Coly,
>=20
> Gentle ping on this series. Patch 1/2 has Coly's Reviewed-by, and
> both patches address:
>=20
> - 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
>=20
> Both are tagged Fixes: and Cc: stable, so happy to resend or rebase
> if anything's needed on my end  just let me know.
>=20
> Thanks,
> Ramesh
>=20
> On Tue, Jul 21, 2026 at 10:11=E2=80=AFPM Ramesh Adhikari
> <[email protected]> wrote:
>>=20
>> Two related fixes to block/badblocks.c:
>>=20
>> 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.
>>=20
>> 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 de=
tails.
>> 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).
>>=20
>> Ramesh Adhikari (2):
>>  badblocks: fix in-place round_up/round_down usage bug
>>  badblocks: validate sector range and shift before rounding
>>=20
>> block/badblocks.c         | 40 ++++++++++++++++++++++++++++++++-------
>> include/linux/badblocks.h |  6 +++++-
>> 2 files changed, 38 insertions(+), 8 deletions(-)
>>=20
>> --
>> 2.43.0
>>