Kernel Bug Tracker – Bug 5133
Ondemand governor makes system unstable
Last modified: 2007-04-29 07:51:45 UTC
Hardware Environment: x86_64
Problem Description: When using ondemand governor the kernel will freeze, reboot
or most of the processes just become unstable after some time of usage.
Steps to reproduce:
start to use ondemand governor:
echo ondemand >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
After some hours, say 1 - 4 h, the system becomes unstable when used normally
(surf net, read mail, etc.)
System might reboot itself without warning, kill X, make some process to behave
oddly before the process dies, etc.
Normally there is no warnings, errors or what so ever. After enabling a kernel
debug I got few backtraces.
If I do not use the ondemand governor then the system works just fine (uptime
+30 days). I haven't changed my kernel configuration for some time so it was
quite easy to spot what caused system to freek out.
I recall that I've seen the same symptoms when using some 2.6.9 - 2.6.10
(Gentoo) kernels with ondemand governor. Back then I just decided to stick with
the default (performance) governor.
Created attachment 5774 [details]
backtraces from 2.6.12-gentoo-r9
Created attachment 5775 [details]
Created attachment 5776 [details]
backtrace from 2.6.13-rc7
Note that the system didn't start to show symptoms immediatetly after backtraces
appeared, but little while after messages (like hour or two).
Created attachment 5831 [details]
backtrace from 2.6.13
I enabled cpufreq debug but I haven't noticed anything interesting, except lot
of 'printk: xx messages suppressed' -messages.
Is there anything that I could do to get this bug fixed?
Downstream bug report: http://bugs.gentoo.org/show_bug.cgi?id=103497
What is the state of this bug?
no response from reporter, marking as NEEDINFO
It seems that the ondemand cpufreq scaling governor has been fixed some where
between 2.6.14 and 2.6.17. Ondemand governor has been my default cpu frequency
governor at least since 2.6.18. I might have used it with 2.6.17.
IIRC I tried to use ondemand with 2.6.14 and 2.6.15 but with same symptoms.
Great, thanks for the update.