Re: Patch "md: call del_gendisk in control path" has been added to the 6.6-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Aug 18, 2025 at 03:13:11PM +0800, Yu Kuai wrote:
> Hi,
> 
> 在 2025/08/18 14:38, Greg KH 写道:
> > On Mon, Aug 18, 2025 at 02:26:23PM +0800, Yu Kuai wrote:
> > > Hi,
> > > 
> > > 在 2025/08/18 13:55, Greg KH 写道:
> > > > On Mon, Aug 18, 2025 at 09:03:39AM +0800, Yu Kuai wrote:
> > > > > Hi,
> > > > > 
> > > > > 在 2025/08/17 22:18, Sasha Levin 写道:
> > > > > > This is a note to let you know that I've just added the patch titled
> > > > > > 
> > > > > >        md: call del_gendisk in control path
> > > > > > 
> > > > > > to the 6.6-stable tree which can be found at:
> > > > > >        http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > > > > > 
> > > > > > The filename of the patch is:
> > > > > >         md-call-del_gendisk-in-control-path.patch
> > > > > > and it can be found in the queue-6.6 subdirectory.
> > > > > > 
> > > > > > If you, or anyone else, feels it should not be added to the stable tree,
> > > > > > please let <stable@vger.kernel.org> know about it.
> > > > > > 
> > > > > > 
> > > > > This patch should be be backported to any stable kernel, this change
> > > > > will break user tools mdadm:
> > > > > 
> > > > > https://lore.kernel.org/all/f654db67-a5a5-114b-09b8-00db303daab7@redhat.com/
> > > > 
> > > > Is it reverted in Linus's tree?
> > > > 
> > > 
> > > No, we'll not revert it, this is an improvement. In order to keep user
> > > tools compatibility, we added a switch in the kernel. As discussed in
> > > the thread, for old tools + new kernel, functionality is the same,
> > > however, there will be kernel warning about deprecated behaviour to
> > > inform user upgrading user tools.
> > > 
> > > However, I feel this new warning messages is not acceptable for
> > > stable kernels.
> > 
> > Why?  What is so special about stable kernels that taking the same
> > functionality in newer kernels is not ok?
> > 
> > Why not just "warn" the same here if you want to fix an issue where
> > userspace should be also updating some tools.  As long as you aren't
> > breaking anything, it should be fine, right?
> 
> Yes, it's fine, just in downstream kernels, people won't be happy about
> new warnings.

People are NEVER happy about new warnings.  So why are you warning them
at all in newer kernels?

> > Or are you breaking existing workflows?  You should be able to take a
> > new kernel without any userspace changes and all should work the same.
> > Why make new kernel users change userspace tools at all?
> 
> There is a pending fix in mdraid that will be pushed soon, with this
> nothing will be broken.

Great, what is the git id?

> And because user tools have problems in this case as well, both kernel
> and user tools have to be fixed to make things better.

So Linus's tree right now doesn't work without the pending fix as well?

thanks,

greg k-h