[regression] segfault in Qt apps running on Linux kernel 6.10.8 ARM with LPAE

[Linux regression tracking (Thorsten Leemhuis)]

Hi, Thorsten here, the Linux kernel's regression tracker.

Catalin, Linus, I noticed a report about a regression in
bugzilla.kernel.org that appears to be caused by a change of yours:

7af5b901e84743 ("ARM: 9358/2: Implement PAN for LPAE by TTBR0 page table
walks disablement") [v6.10-rc1]

As many (most?) kernel developers don't keep an eye on the bug tracker,
I decided to write this mail. To quote from https://bugzilla.kernel.org/
show_bug.cgi?id=219247 :

> Trying to run LxQt on a Chromebook XE303C12 with Devuan 4 and Linux
> kernel 6.10.8 results in a segmentation fault (for LxQt). There are
> no such problems with Linux kernel 6.9.12 or earlier. With Linux
> kernel 6.10.8 it is possible to run Xfce4, but trying to run for
> example Kate ends in a segmentation fault. Mesa 20.3.5, patched for
> partial hardware acceleration, preserves this acceleration in Xfce4.
> The mpv works using acceleration regardless of the Linux kernel
> version. dmesg does not give anything significantly new compared to
> previous kernel version.

See the ticket for more details and the bisection log. The reporter is CCed.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

P.S.: let me use this mail to also add the report to the list of tracked
regressions to ensure it's doesn't fall through the cracks:

#regzbot introduced: 7af5b901e84743c608aae90cb0e429702812c324
#regzbot title: ARM: segfault in Qt apps running on Linux kernel 6.10.8
ARM with LPAE
#regzbot from: Andrew
#regzbot duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=219247
#regzbot ignore-activity