[Intel-wired-lan] [net v2 0/5] igb: fix ptp suspend/resume issue

Brown, Aaron F aaron.f.brown at intel.com
Tue May 17 21:05:25 UTC 2016


> From: Keller, Jacob E
> Sent: Tuesday, May 17, 2016 1:47 PM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher at intel.com>; Brown, Aaron F
> <aaron.f.brown at intel.com>; intel-wired-lan at lists.osuosl.org
> Cc: sagar.tv at gmail.com
> Subject: Re: [Intel-wired-lan] [net v2 0/5] igb: fix ptp suspend/resume issue
> 
> On Mon, 2016-05-16 at 19:29 -0700, Jeff Kirsher wrote:
> > On Tue, 2016-05-17 at 01:57 +0000, Brown, Aaron F wrote:
> > >
> > > >
> > > > From: Intel-wired-lan [mailto:intel-wired-lan-bounces at lists.osuos
> > > > l.org]
> > > On
> > > >
> > > > Behalf Of Jacob Keller
> > > > Sent: Wednesday, May 11, 2016 4:18 PM
> > > > To: Intel Wired LAN <intel-wired-lan at lists.osuosl.org>
> > > > Cc: Vidya Sagar <sagar.tv at gmail.com>
> > > > Subject: [Intel-wired-lan] [net v2 0/5] igb: fix ptp
> > > > suspend/resume
> > > issue
> > > >
> > > >
> > > > This patch series (properly) fixes the issue with igb's workqueue
> > > > item
> > > > for overflow check from causing a surprise remove event. To do
> > > > this,
> > > > properly suspend the workqueue items in suspend and then resume
> > > > them
> > > > again during the resume flow.
> > > >
> > > > The patch series has a few extra steps to reduce code duplication
> > > > and
> > > > implement suspend and resume properly, which makes the overall
> > > > fix a
> > > bit
> > > >
> > > > more complicated, and thus review is welcome.
> > > >
> > > > A smaller fix would be to implement suspend and resume
> > > > irrespective of
> > > > the current igb_ptp_stop and igb_ptp_init but this seems more
> > > > likely to
> > > > introduce bugs especially if either function ever changes in the
> > > future.
> > > >
> > > >
> > > > In addition, the ptp_flags variable is added mostly to simplify
> > > > the
> > > work
> > > >
> > > > of writing several complex MAC type checks in the ptp code while
> > > > doing
> > > > this.
> > > >
> > > > Jacob Keller (5):
> > > >    igb: introduce ptp_flags variable and use it to replace
> > > > IGB_FLAG_PTP
> > > >    igb: introduce IGB_PTP_OVERFLOW_CHECK flag
> > > >    igb: introduce igb_ptp_resume function
> > > >    igb: implement igb_ptp_suspend
> > > >    igb: call igb_ptp_suspend/igb_ptp_resume during suspend/resume
> > > > cycle
> > > >
> > > >   drivers/net/ethernet/intel/igb/igb.h      |   8 ++-
> > > >   drivers/net/ethernet/intel/igb/igb_main.c |   4 +-
> > > >   drivers/net/ethernet/intel/igb/igb_ptp.c  | 110
> > > > ++++++++++++++++----
> > > ---------
> > > >
> > > > -
> > > >   3 files changed, 68 insertions(+), 54 deletions(-)
> > > I have not isolated it to the exact patch yet, but one of the
> > > patches in
> > > this series is causing my systems to lock up with a call trace.  I
> > > am
> > > currently unable to capture the trace in any form other than a
> > > bitmap
> > > (which I'll send to Jacob but am not attaching here.)  The trace is
> > > really several splats a few minutes apart.  The exact text /
> > > procedure
> > > calls of the first one seems to vary, but it seems to be in a
> > > wakeup
> > > routing with "do_page_fault", "? _raw_spin_lock_irq", "?
> > > timecounter_read", "? _raw_spin_lock_irqsave",
> > > "igb_ptp_gettime_82576"
> > > and "igb_ptp_overflow_check" showing up prominently in at least a
> > > few
> > > instances.  Usually it moves to the next trace before I can get a
> > > snapshot.  The follow on trace is where it usually stops with a
> > > RIP:,
> > > bunch of hex, stack info and a Call Trace saying "arch_cpu_idle",
> > > "default_idle_call", "cpu_startup_entry" and "start_secondary"
> > > called
> > > out.
> > Andrew thought it was with patch 3 in the series, at least that is
> > what his
> > initial git bisect was telling him.
> >
> > I am going to go ahead and drop the entire series for now, so that we
> > can
> > work offline to resolve the issue.
> 
> 
> Yep. I'm investigating the traces. I'll focus my initial efforts at
> patch 3.

I can confirm Andrew's bisection and that the issue does not start occurring until patch 3 is included.

> 
> Thanks,
> Jake


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