Re: [GIT PULL] KVM changes for 4.18 merge window

Greg Kroah-Hartman
2018-06-13T04:47:38Z

On Tue, Jun 12, 2018 at 08:26:46PM -0700, Linus Torvalds wrote:
> On Tue, Jun 12, 2018 at 8:00 PM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > Yeah, the biusection seems to actually be diving into Greg's device pulls.
> >
> > Odd. I'm not seeing why that would break kvm, but maybe there's
> > something in the device core layer that really messed it up.
> >
> > I'll continue to bisect to see.
>
> Ok, so commit 95cde3c59966 ("debugfs: inode: debugfs_create_dir uses
> mode permission from parent") breaks lkvm, and I think qemu-kvm too.
>
> The commit looks like the RightThing(tm) to do, but we do not break
> existing work-flows, no matter how much we'd like to. So it gets
> reverted.
>
> Greg, Thomas, perhaps some alternative model? I'm not sure exactly
> what kvm needs from debugfs.

I don't know either, I have a revert of that patch sitting in my queue
waiting to send to you for 4.18-rc1. I didn't realize it was causing
breakage for others, or I would have sent it to you now. You can revert
it yourself now if you want, so we can fix this problem now and work on
figuring out what is so "odd" about kvm's debugfs files.

thanks,

greg k-h