Re: [REGRESSION] Chrome and VSCode breakage with the commit b9b588f22a0c

[Takashi Iwai <tiwai@suse.de>]

On Wed, 26 Feb 2025 15:35:34 +0100,
Greg KH wrote:
> 
> On Wed, Feb 26, 2025 at 03:26:44PM +0100, Greg KH wrote:
> > On Wed, Feb 26, 2025 at 09:20:20AM -0500, Chuck Lever wrote:
> > > On 2/26/25 9:16 AM, Takashi Iwai wrote:
> > > > On Wed, 26 Feb 2025 15:11:04 +0100,
> > > > Chuck Lever wrote:
> > > >>
> > > >> On 2/26/25 3:38 AM, Takashi Iwai wrote:
> > > >>> On Sun, 23 Feb 2025 16:18:41 +0100,
> > > >>> Chuck Lever wrote:
> > > >>>>
> > > >>>> On 2/23/25 3:53 AM, Takashi Iwai wrote:
> > > >>>>> [ resent due to a wrong address for regression reporting, sorry! ]
> > > >>>>>
> > > >>>>> Hi,
> > > >>>>>
> > > >>>>> we received a bug report showing the regression on 6.13.1 kernel
> > > >>>>> against 6.13.0.  The symptom is that Chrome and VSCode stopped working
> > > >>>>> with Gnome Scaling, as reported on openSUSE Tumbleweed bug tracker
> > > >>>>>   https://bugzilla.suse.com/show_bug.cgi?id=1236943
> > > >>>>>
> > > >>>>> Quoting from there:
> > > >>>>> """
> > > >>>>> I use the latest TW on Gnome with a 4K display and 150%
> > > >>>>> scaling. Everything has been working fine, but recently both Chrome
> > > >>>>> and VSCode (installed from official non-openSUSE channels) stopped
> > > >>>>> working with Scaling.
> > > >>>>> ....
> > > >>>>> I am using VSCode with:
> > > >>>>> `--enable-features=UseOzonePlatform --enable-features=WaylandWindowDecorations --ozone-platform-hint=auto` and for Chrome, I select `Preferred Ozone platform` == `Wayland`.
> > > >>>>> """
> > > >>>>>
> > > >>>>> Surprisingly, the bisection pointed to the backport of the commit
> > > >>>>> b9b588f22a0c049a14885399e27625635ae6ef91 ("libfs: Use d_children list
> > > >>>>> to iterate simple_offset directories").
> > > >>>>>
> > > >>>>> Indeed, the revert of this patch on the latest 6.13.4 was confirmed to
> > > >>>>> fix the issue.  Also, the reporter verified that the latest 6.14-rc
> > > >>>>> release is still affected, too.
> > > >>>>>
> > > >>>>> For now I have no concrete idea how the patch could break the behavior
> > > >>>>> of a graphical application like the above.  Let us know if you need
> > > >>>>> something for debugging.  (Or at easiest, join to the bugzilla entry
> > > >>>>> and ask there; or open another bug report at whatever you like.)
> > > >>>>>
> > > >>>>> BTW, I'll be traveling tomorrow, so my reply will be delayed.
> > > >>>>>
> > > >>>>>
> > > >>>>> thanks,
> > > >>>>>
> > > >>>>> Takashi
> > > >>>>>
> > > >>>>> #regzbot introduced: b9b588f22a0c049a14885399e27625635ae6ef91
> > > >>>>> #regzbot monitor: https://bugzilla.suse.com/show_bug.cgi?id=1236943
> > > >>>>
> > > >>>> We received a similar report a few days ago, and are likewise puzzled at
> > > >>>> the commit result. Please report this issue to the Chrome development
> > > >>>> team and have them come up with a simple reproducer that I can try in my
> > > >>>> own lab. I'm sure they can quickly get to the bottom of the application
> > > >>>> stack to identify the misbehaving interaction between OS and app.
> > > >>>
> > > >>> Do you know where to report to?
> > > >>
> > > >> You'll need to drive this, since you currently have a working
> > > >> reproducer.
> > > > 
> > > > No, I don't have, I'm merely a messenger.
> > > 
> > > Whoever was the original reporter has the ability to reproduce this and
> > > answer any questions the Chrome team might have. Please have them drive
> > > this. I'm already two steps removed, so it doesn't make sense for me to
> > > report a problem for which I have no standing.
> > 
> > Ugh, no.  The bug was explictly bisected to the offending commit.  We
> > should just revert that commit for now and it can come back in the
> > future if the root-cause is found.
> > 
> > As the revert seems to be simple, and builds here for me, I guess I'll
> > have to send it in. {sigh}
> > 
> > Takashi, thanks for the report and the bisection, much appreciated.
> 
> Now sent:
> 	https://lore.kernel.org/r/2025022644-blinked-broadness-c810@gregkh

Thanks Greg!

Let's continue hunting the cause before 6.14 release, meanwhile.


Takashi