Red Hat Bugzilla – Bug 592785
usb kvm switch sometimes kernel oops dev_get_drvdata
Last modified: 2010-08-23 18:02:08 EDT
Description of problem:
I have a USB/DVI KVM switch and I switch between the F12 box and an XP box sometimes hundreds of times an hour. Once in a blue moon F12 oops's and goes wonky. No rhyme or reason to it. Sometimes I'll switch 1000+ times without issue. XP box never seems to have a problem.
May 16 15:36:22 pog kernel: BUG: unable to handle kernel NULL pointer dereference at 00000020
May 16 15:36:22 pog kernel: IP: [<c0660028>] dev_get_drvdata+0xc/0x1c
May 16 15:36:22 pog kernel: *pdpt = 000000001719c001 *pde = 00000000c6f04067
May 16 15:36:22 pog kernel: Oops: 0000 [#1] SMP
attaching more output
Version-Release number of selected component (if applicable):
difficult, seemingly random and at extremely long intervals
Steps to Reproduce:
1. switch computers on KVM switch often
oops, can't gain control of mouse/keyboard after that, remote logins start freezing
system runs fine, kb/mse work fine
tainted with nvidia binary driver from rpm-fusion, sorry
Created attachment 414421 [details]
more detailed dmesg output
Created attachment 421519 [details]
The fix (2 commits)
Are you able to test above fix, or should I prepare test kernel for you?
Hi, I haven't done a kernel compile in a few years. I stick to the stock Fedora ones mostly now. I'm on F12 currently.
I could run a test kernel you provide if it won't mess up my F12 system. Of course, if security errata is issued I'd be forced to go back to stock ones.
This bug is so obscure (only hit me once) it may be a difficult one to test for: hard to tell if it's fixed or just not hitting the pathological case.
But I will help out however I can. Thanks!
I looked at patch and oops messages again, I'm pretty sure patch fix the problem. I will post patch to fedora-kernel mailing list, it should be included soon in F-12 kernel. F-13 will switch to 2.6.34 kernel, so problem will be fixed there as well.
Patch went in 126.96.36.199-157
kernel-188.8.131.52-162.fc12 has been submitted as an update for Fedora 12.
kernel-184.108.40.206-163.fc12 has been submitted as an update for Fedora 12.
kernel-220.127.116.11-163.fc12 has been pushed to the Fedora 12 testing repository. If problems still persist, please make note of it in this bug report.
If you want to test the update, you can install it with
su -c 'yum --enablerepo=updates-testing update kernel'. You can provide feedback for this update here: http://admin.fedoraproject.org/updates/kernel-18.104.22.168-163.fc12
Thanks, I'll try it out and report back if the oops happens again. However, like I said before, this bug is very very rare so no recurrence in a reasonable timeframe doesn't necessarily mean it's fixed.
Sure, just reopen bug if you see the problem again, but I believe you will not see it because is fixed :-)
kernel-22.214.171.124-163.fc12 has been pushed to the Fedora 12 stable repository. If problems still persist, please make note of it in this bug report.