Re: NOHZ: local_softirq_pending 08

[Nikos Chantziaras <realnc@gmail.com>]

On 31/05/12 17:04, Dave Jones wrote:
> On Thu, May 31, 2012 at 09:56:25AM +0200, Eric Dumazet wrote:
>   > On Thu, 2012-05-31 at 09:52 +0200, Thomas Gleixner wrote:
>   > > Dave,
>   > >
>   > > On Wed, 30 May 2012, Dave Jones wrote:
>   > >
>   > > > May 30 17:43:04 [ 1095.335659] NOHZ: local_softirq_pending 08
>   > > >
>   > > > According to git, you ratelimited this back in 2007 with the message
>   > > > "until we found the root cause of that problem."
>   > > >
>   > > > Is this an old problem that has returned ?
>   > >
>   > > Looks like.
>   > >
>   > > > Maybe interesting note: Both machines I see this on regularly are Atom cpus,
>   > > > and it's always '08'.
>   > >
>   > > So it goes idle with NET_RX softirq pending. That really should not
>   > > happen. I fear you need to fire up the tracer :)
>   >
>   > It might be a bug in the network driver, a race with NAPI completion.
>   >
>   > Dave, which net drivers run on these machines ?
>
> r8169.
>
> I got an email from someone else asking if I used Realtek drivers, which I thought
> was an uncanny guess.

Same thing happens here (kernel 3.4.1, also happened with 3.4.0):

r8169 0000:06:00.0: eth0: link down
r8169 0000:06:00.0: eth0: link down
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
r8169 0000:06:00.0: eth0: link up