Jaervosz' burrow

Coming Underground

2008-06-24 22:57, by jaervosz, Categories: General, Gentoo, Universe/English

Arggh it just happened again!

From time to time I run into a strange problem with Xorg on my hardened laptop and the mouse pointer on screen jumps to the upper left corner of the screen and stays there:-(

AFAIR the problem have persisted across several Xorg versions so I'm wondering wether it's something hardware specific or perhaps related to hardened. Though I haven't really had the time to dig into it.

UPDATE: Thx to Gordon Malm for solving the issue. It's indeed caused by CONFIG_PAX_KERNEXEC as described in Using Xorg on Hardened Gentoo.

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Comment from: Stavros Christoforou [Visitor]

If the pointer is moving towards the end, then stays there for 3-4 seconds, after which you can move it again, it is not an Xorg/Linux problem, it is the trackpoint recalibrating itself.

2008-06-24 @ 23:17

Comment from: vivo [Visitor]

when it happened to me it was the cheap optical mouse over a non uniform surface, only happened seldomly tough.

2008-06-24 @ 23:18

Comment from: Gordon Malm [Visitor]

This is a common interaction with X and the hardened kernel's PaX KERNEXEC feature. See item #2 here:

http://www.gentoo.org/proj/en/hardened/hardenedxorg.xml

Turning off PAX_KERNEXEC will likely stop the problem.

2008-06-24 @ 23:36

Comment from: Tiago Cunha [Visitor]

I hit this bug back in 2006.
According to freedesktop's bug #3113 its fixed. HTH.

2008-06-25 @ 05:31

Comment from: Gordon Malm [Visitor]

I've been doing some research/testing on this issue. It seems to be an interaction between forced-preemption and KERNEXEC. You should be able to re-enable KERNEXEC as long as you disable preemption or use voluntary preemption.

2008-08-09 @ 03:50

Comment from: Hugo Mildenberger [Visitor]

Gordon, thank you very much for your hint to forced preemption. After switching to voluntary preemption the problem indeed was gone on Gentoo 2.6.28-hardened-r3.

2009-03-17 @ 01:52

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