Re: [3.5.4] rcu_sched self-detected stall on CPU { 1} (t=54862991 jiffies)

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Sep 25, 2012 at 06:31:36PM +0200, Paweł Sikora wrote:
> On Monday 24 of September 2012 10:36:33 Greg KH wrote:
> > On Mon, Sep 24, 2012 at 10:05:23AM +0200, Paweł Sikora wrote:
> > > Hi,
> > > 
> > > with the new stable line i'm observing strange locks on my old amd-phenom-II mini-server.
> > > here's a dmesg:
> > 
> > Did this show up in 3.5.3?  If not, can you run 'git bisect' to find the
> > problem patch?
> 
> heh, the old good kernel put some light on this issue.
> 
> Sep 25 08:50:24 nexus kernel: [60330.301639] Clocksource tsc unstable (delta = -474690884 ns)
> Sep 25 08:50:24 nexus kernel: [60330.325477] ------------[ cut here ]------------
> Sep 25 08:50:24 nexus kernel: [60330.325484] WARNING: at /home/users/builder/rpm/BUILD/kernel-2.6.37.6/linux-2.6.37/net/sched/sch_generic.c:258 dev_watchdog+0x25d/0x270()
> Sep 25 08:50:24 nexus kernel: [60330.325486] Hardware name: GA-MA785GMT-UD2H
> Sep 25 08:50:24 nexus kernel: [60330.325487] NETDEV WATCHDOG: eth0 (r8169): transmit queue 0 timed out
> (...)
> Sep 25 08:50:25 nexus kernel: [60330.851093] Switching to clocksource acpi_pm
> 
> afaics, this amd-phenom cpu does the cpu frequency scaling and causes plain 'tsc' timer
> instability which leads to network card watchdog timeout (i can login via local console
> while any network traffic is dead). on the recent 3.5.x kernel the 'clocksource unstable'
> message appears *after* 'task blocked' flood and there's no clear info about watchog timeout.
> currently i'm testing hpet clocksource becasue better tsc modes (constant_tsc, nonstop_tsc)
> aren't present in /sys/devices/system/clocksource/clocksource0/available_clocksource while
> cpu supports them.

I'm sorry, I don't understand, that's a 2.6.37 kernel you are comparing
this to.  Where did this problem show up?  In 3.5.4 where 3.5.3 was
fine?

Or somewhere else?

confused,

greg k-h