Red Hat Bugzilla – Bug 461756
Crash when I switch to another display using a KVM switch
Last modified: 2013-01-09 23:47:50 EST
Created attachment 316305 [details]
Description of problem:
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Stick a usb KVM switch into a rawhide x86_64 box
2. Switch to another display, switch back
3. X has exited and restarted
I imagine that the same effect might be seen if a usb keyboard is simply unplugged, without any KVM in the loop
X driver itself doesn't matter, logs here will be with nouveau, but happens with vesa too
Created attachment 316308 [details]
Xorg.0.conf before switching
Created attachment 316310 [details]
Xorg.0.conf.old after switching back
Presumably this is the magic bit...
(II) UnloadModule: "evdev"
0: /usr/bin/Xorg(xf86SigHandler+0x65) [0x47a105]
1: /lib64/libc.so.6 [0x3538a33130]
2: /usr/lib64/xorg/modules/input//evdev_drv.so [0x7f5bbee9bd00]
3: /usr/bin/Xorg [0x4e4498]
4: /usr/bin/Xorg(WaitForSomething+0x56b) [0x4e4aeb]
5: /usr/bin/Xorg(Dispatch+0x7f) [0x4465ff]
6: /usr/bin/Xorg(main+0x45d) [0x42ccbd]
7: /lib64/libc.so.6(__libc_start_main+0xe6) [0x3538a1e566]
8: /usr/bin/Xorg [0x42c099]
I guess on switch away evdev gets unloaded causing the trouble
The F-9 box switched-to survives fine, and all is well if I drop to a vt on the rawhide box, switch, switch-back, and restore the X vt
I've seen this before, but I haven't been able to reproduce it. There must be some magic trigger. Funnily enough, I have a mouse that dies about every second and gets removed and re-added and I have yet to trigger this.
What I think happens is that the event is processed after the mouse has been deleted + freed already. How that happens is unclear as of yet.
Here's how I can reproduce this.
At gdm hold down a key on the usb keyboard, e.g. a and pull out the usb mouse, stick the mouse back end, and release the key. Wait a few secs, now hold down the same key again and pull out the mouse. ka-pow, death
I can produce this easily by having both the keyboard and mouse go away. I've reproduced it both during installs (keyboard/mouse fed by usb) and on my laptop. During installs I kvm switch away. On my laptop I just shut off the LCD monitor, which is acting as a USB hub for my keyboard/mouse.
Since this is very easily triggered, I'm marking it a beta blocker.
My fault. I did patch it, but being offline it never went into CVS.
Please try xorg-x11-drv-evdev-2.0.4-3, ajax committed the fix for it.
Believe this is fixed in 2.0.4-3. Closing. Please reopen if this doesn't fix it for you.