Re: "loop: Avoid updating block size under exclusive owner" breaks on 6.6.103

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Sep 17, 2025 at 05:47:16PM +0200, Jan Kara wrote:
> On Wed 17-09-25 11:18:50, Eric Hagberg wrote:
> > I stumbled across a problem where the 6.6.103 kernel will fail when
> > running the ioctl_loop06 test from the LTP test suite... and worse
> > than failing the test, it leaves the system in a state where you can't
> > run "losetup -a" again because the /dev/loopN device that the test
> > created and failed the test on... hangs in a LOOP_GET_STATUS64 ioctl.
> > 
> > It also leaves the system in a state where you can't re-kexec into a
> > copy of the kernel as it gets completely hung at the point where it
> > says "starting Reboot via kexec"...
> 
> Thanks for the report! Please report issues with stable kernels to
> stable@vger.kernel.org (CCed now) because they can act on them.
> 
> > If I revert just that patch from 6.6.103 (or newer) kernels, then the
> > test succeeds and doesn't leave the host in a bad state. The patch
> > applied to 6.12 doesn't cause this problem, but I also see that there
> > are quite a few other changes to the loop subsystem in 6.12 that never
> > made it to 6.6.
> > 
> > For now, I'll probably just revert your patch in my 6.6 kernel builds,
> > but I wouldn't be surprised if others stumble across this issue as
> > well, so maybe it should be reverted or fixed some other way.
> 
> Yes, I think revert from 6.6 stable kernel is warranted (unless somebody
> has time to figure out what else is missing to make the patch work with
> that stable branch).

Great, can someone send me the revert?

thanks,

greg k-h