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

[Jeff Kirsher]

On Tue, 2016-05-17 at 01:57 +0000, Brown, Aaron F wrote:
> > From: Intel-wired-lan [mailto:intel-wired-lan-bounces at lists.osuosl.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.
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