Annoying "2.6.31+ kernel detected" errors

Discussions related to using VirtualBox on Linux hosts.

Annoying "2.6.31+ kernel detected" errors

Postby Prikrutil » 1. Aug 2010, 19:34

Every time my system loads vboxdrv, the following message is written to errors.log:

Code: Select all   Expand viewCollapse view
Jul 22 18:32:02 myhost kernel: vboxdrv: Warning: 2.6.31+ kernel detected. Most likely the hardware performance
Jul 22 18:32:02 myhost kernel: vboxdrv: counter framework which can generate NMIs is active. You have to prevent
Jul 22 18:32:02 myhost kernel: vboxdrv: the usage of hardware performance counters by
Jul 22 18:32:02 myhost kernel: vboxdrv:   echo 2 > /proc/sys/kernel/perf_counter_paranoid


My errors.log is full of these messages and I can't do anything with this, because there is no "/proc/sys/kernel/perf_counter_paranoid" file in my system.

Also I'm not sure that doing "echo 2 > /proc/sys/kernel/perf_counter_paranoid" before loading vboxdrv would make these errors go away. According to http://www.virtualbox.org/browser/trunk ... nux.c#L500, no matter what /proc/sys/kernel/perf_counter_paranoid file contains, the error will always be logged.

Will the coming VirtualBox 3.2.8 have the same issue?

Host OS: Archlinux i686 with 2.6.34.1 kernel
VirtualBox: PUEL v3.2.6

Thanks.
Prikrutil
 
Posts: 4
Joined: 1. Aug 2010, 18:09
Primary OS: Linux other
VBox Version: PUEL
Guest OSses: Arch Linux

Re: Annoying "2.6.31+ kernel detected" errors

Postby Frank Mehnert » 3. Aug 2010, 09:50

These messages are not real errors (although printed with the KERN_ERR tag) but warnings. The real fix which makes this message obsolete is quite complicated and even VBox 3.2.8 will not contain it. For now it is important to not use hardware-aided performance counters on the host while running VMs with VirtualBox, therefore the warning.
Frank Mehnert
Oracle Corporation
 
Posts: 2523
Joined: 7. Jun 2007, 09:11
Location: Dresden, Germany
Primary OS: Debian Lenny
VBox Version: PUEL
Guest OSses: Linux, Windows

Re: Annoying "2.6.31+ kernel detected" errors

Postby Prikrutil » 3. Aug 2010, 12:08

Frank Mehnert, thanks for your answer.

According to your letter in mailing list http://vbox.innotek.de/pipermail/vbox-d ... 02860.html /proc/sys/kernel/perf_event_paranoid has to be used instead of /proc/sys/kernel/perf_counter_paranoid

So there are two quite easy to implement in 3.2.8 things which will make this message go away until the real fix is ready

1. Change /proc/sys/kernel/perf_counter_paranoid to /proc/sys/kernel/perf_event_paranoid in the warning message
2. If /proc/sys/kernel/perf_event_paranoid already contains 2, there shouldn't be any warnings in errors.log

Having errors.log full of warning messages I can't really fix is really annoying :(

Thanks!
Prikrutil
 
Posts: 4
Joined: 1. Aug 2010, 18:09
Primary OS: Linux other
VBox Version: PUEL
Guest OSses: Arch Linux

Re: Annoying "2.6.31+ kernel detected" errors

Postby Prikrutil » 3. Aug 2010, 12:27

Prikrutil wrote:So there are two quite easy to implement in 3.2.8 things which will make this message go away


Here I mean that user won't see warnings if he/she already has done "echo 2 > /proc/sys/kernel/perf_event_paranoid"
Prikrutil
 
Posts: 4
Joined: 1. Aug 2010, 18:09
Primary OS: Linux other
VBox Version: PUEL
Guest OSses: Arch Linux

Re: Annoying "2.6.31+ kernel detected" errors

Postby Prikrutil » 5. Aug 2010, 13:27

I submitted ticket for this: http://www.virtualbox.org/ticket/7273
Prikrutil
 
Posts: 4
Joined: 1. Aug 2010, 18:09
Primary OS: Linux other
VBox Version: PUEL
Guest OSses: Arch Linux


Return to VirtualBox on Linux Hosts

Who is online

Users browsing this forum: No registered users and 22 guests