Re: [PATCH 6.15 000/588] 6.15.4-rc2 review

[Holger Hoffstätte]

On 2025-06-25 10:25, Greg Kroah-Hartman wrote:
> On Wed, Jun 25, 2025 at 10:00:56AM +0200, Holger Hoffstätte wrote:
> > (cc: Christian Brauner>
> >
> > Since 6.15.4-rc1 I noticed that some KDE apps (kded6, kate (the text editor))
> > started going into a tailspin with 100% per-process CPU.
> >
> > The symptom is 100% reproducible: open a new file with kate, save empty file,
> > make changes, save, watch CPU go 100%. perf top shows copy_to_user running wild.
> >
> > First I tried to reproduce on 6.15.3 - no problem, everything works fine.
> >
> > After checking the list of patches for 6.15.4 I reverted the anon_inode series
> > (all 3 for the first attempt) and the problem is gone.
> >
> > Will try to reduce further & can gladly try additional fixes, but for now
> > I'd say these patches are not yet suitable for stable.
>
> Does this same issue also happen for you on 6.16-rc3?

Curiously it does *not* happen on 6.16-rc3, so that's good.
I edited/saved several files and everything works as it should.

In 6.15.4-rc the problem occurs (as suspected) with:
anon_inode-use-a-proper-mode-internally.patch aka cfd86ef7e8e7 upstream.

thanks
Holger