[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 22:01:21 UTC 2016


> From: Keller, Jacob E
> Sent: Tuesday, May 17, 2016 2:54 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 Tue, 2016-05-17 at 21:05 +0000, Brown, Aaron F wrote:
> > >
> > > 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.o
> > > > > > suos
> > > > > > 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.
> 
> 
> Does this just occur from loading? or does it occur after some action
> on your part?

I initially ran into it just loading the driver and launching a BAT.  But after trying to figure out which section of the BAT was breaking it, I noticed another system I had simply loaded the driver on would lock up after a while as well.  I do not know if it shows up sooner or later if the interface is getting traffic across it, but it shows up either way.

> 
> Thanks,
> Jake


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