Re: Fwd: Fwd: X stopped working with 5.14 on iBook

On Wednesday, November 3rd, 2021 at 4:26 PM, Finn Thain [off-list ref] wrote:

On Wed, 3 Nov 2021, Andreas Schwab wrote:

quoted

On Nov 02 2021, Finn Thain wrote:

quoted

After many builds and tests, Stan and I were able to determine that this

regression only affects builds with CONFIG_USER_NS=y. That is,

d3ccc9781560 + CONFIG_USER_NS=y --> fail

d3ccc9781560 + CONFIG_USER_NS=n --> okay

d3ccc9781560~ + CONFIG_USER_NS=y --> okay

d3ccc9781560~ + CONFIG_USER_NS=n --> okay

On my iBook G4, X is working alright with 5.15 and CONFIG_USER_NS=y.

Stan said his Cube has these packages installed:

dpkg --list | grep Xorg
=======================

ii xserver-xorg-core 2:1.20.11-1

powerpc Xorg X server - core server

ii xserver-xorg-legacy 2:1.20.11-1

powerpc setuid root Xorg server wrapper

I gather that Riccardo also runs Debian SID.

Perhaps there is some interaction between d3ccc9781560, CONFIG_USER_NS and

the SUID wrapper...

Does your Xorg installation use --enable-suid-wrapper, Andreas?

Hi Andreas,

Does X work for you if you use the current Debian SID installation with their current default kernel? That's how this all started. The problem was eventually isolated via a git bisect and an exhaustive search of kernel options to the identified "bad commit" and the kernel option CONFIG_USER_NS. The kernel just before the bad commit works with or without CONFIG_USER_NS set, but as of the bad commit, X works only with CONFIG_USER_NS not set, at least on my G4 Cube.

Hi Riccardo,

The G3 system I used for testing was a PowerBook Series II Wallstreet, using the same kernel and Xorg versions that I'm using on the Cube. The same test that failed on the Cube worked on the Wallstreet. Of course, this result may not be consistent with other G3 systems. On your iBook G4, if you recompile the kernel (the one that results in an X that doesn't work on your system) and set CONFIG_USER_NS=n, does X then work?

-Stan