Re: [EXTERNAL] Re: [PATCH 0/1] RFC: linux-5.15.y ksmbd backport for CVE-2023-38431

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Dec 14, 2023 at 08:31:44AM +0900, Namjae Jeon wrote:
> 2023-12-13 23:36 GMT+09:00, Greg KH <gregkh@linuxfoundation.org>:
> > On Tue, Dec 12, 2023 at 08:13:37PM +0000, Steven French wrote:
> >> Out of curiosity, has there been an alternative approach for some
> >> backports, where someone backports most fixes and features (and safe
> >> cleanup) but does not backport any of the changesets which have
> >> dependencies outside the module (e.g. VFS changes, netfs or mm changes
> >> etc.)  to reduce patch dependency risk (ie 70-80% backport instead of
> >> the typical 10-20% that are picked up by stable)?
> >>
> >> For example, we (on the client) ran into issues with 5.15 kernel (for
> >> the client) missing so many important fixes and features (and
> >> sometimes hard to distinguish when a new feature is also a 'fix') that
> >> I did a "full backport" for cifs.ko again a few months ago for 5.15
> >> (leaving out about 10% of the patches, those with dependencies or that
> >> would be risky).
> >
> > We did take a "big backport/sync" for io_uring in 5.15.y a while ago, so
> > there is precident for this.
> >
> > But really, is anyone even using this feature in 5.15.y anyway?  I don't
> > know of any major distro using 5.15.y any more, and Android systems
> > based on 5.15.y don't use this specific filesystem, so what is left?
> > Can we just mark it broken and be done with it?
> As I know, ksmbd is enable in 5.15 kernel of some distros(opensuse,
> ubuntu, etc) except redhat.

But do any of them actually use the 5.15.y kernel tree and take updates
from there?  That's the key thing here.

> And users can use this feature. I will
> make the time for ksmbd backporting job. To facilitate backport, Can I
> submit clean-up patches for ksmbd of 5.15 kernel or only bug fixes are
> allowed?

If a fix relies on an upstream cleanup, that's fine to take.

But first, find out if anyone is actually using this before you take the
time here.

thanks,

greg k-h