Re: [PATCH RESEND 0/5] block: validate direct I/O memory alignment

On 7/30/26 13:26, Christoph Hellwig wrote:
> On Wed, Jul 29, 2026 at 02:03:07PM -0600, Keith Busch wrote:
>>>> Hi Jens, have you had a chance to look at this one yet? This addresses
>>>> previous issues with certain device mappers under direct io.
>>>
>>> I they look fine, but at this point we should toss them into 7.3. Yes
>>> I know there are regressions around this, but from 6.1x days. And the
>>> series doesn't apply to the current block-7.2 anyway.
>>
>> This series is kind of old at this point, but yes, it's not fixing a new
>> regression either. I'm okay if this goes to the next window, and I will
>> handle the stable follow-up.
> 
> Honestly, I think that'a a reall bad idea.  This is a regression in 6.18,
> and while it took a while for people to hit this with their a little
> more complicated lvm/md setups, it has stopped real systems from being
> used.  We need to fix this ASAP.
Thx for this, as I had been thinking along the same lines already and
was still considering if I wanted to speak up.

6.18 still qualifies as recent in my book, but YMMV. And it's not like
people "took forever to notice"[1], as they reported this for a while
now -- and there were a few attempts to fix this; it just took us some
time to see the full problem (@Keith: many thx for that and the fixes
for them). And some of the linked reports are quite recent, so people
really hit this.

Sure, as always there is the risk that this will cause other, bigger
regressions. Maybe that's why it's one of those situations where the
right approach is "submit this separately to Linus and let him decide",
unless of course he speaks up here.

Another reason to maybe merge this now is that Btrfs regression that
likely will only be fixed next week[2] -- so we already risk needing an
rc8 anyway.

Ciao, Thorsten

[1]
https://lore.kernel.org/all/CAHk-=wis_qQy4oDNynNKi5b7Qhosmxtoj1jxo5wmB6SRUwQUBQ@mail.gmail.com/
[2]
https://lore.kernel.org/linux-btrfs/69d0043e0f6a3d17048dfde857127ab0bf331154.1785190866.git.boris@bur.io/