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

Chuck Lever
2025-02-26T15:56:58Z

On 2/26/25 9:26 AM, 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}

Note that reverting also reintroduces a CVE.

--
Chuck Lever