Re: [PATCH] igc: Avoid possible deadlock during suspend/resume

[Stefan Dietrich <roots@gmx.de>]

Hi Thorsten,

thanks for keeping an eye on the issue. I've sent the files in private
because I did not want to spam the mailing lists with them. Please let
me know if this is the correct procedure.


Cheers,
Stefan


On Fri, 2021-12-10 at 10:40 +0100, Thorsten Leemhuis wrote:
> Hi, this is your Linux kernel regression tracker speaking.
>
> On 02.12.21 23:34, Vinicius Costa Gomes wrote:
> > Hi Stefan,
> >
> > Stefan Dietrich <roots@gmx.de> writes:
> >
> > > Hi Vinicius,
> > >
> > > thanks for the patch - unfortunately it did not solve the issue
> > > and I
> > > am still getting reboots/lockups.
> > >
> >
> > Thanks for the test. We learned something, not a lot, but
> > something: the
> > problem you are facing is PTM related and it's not the same bug as
> > that
> > PM deadlock.
> >
> > I am still trying to understand what's going on.
> >
> > Are you able to send me the 'dmesg' output for the two kernel
> > configs
> > (CONFIG_PCIE_PTM enabled and disabled)? (no need to bring the
> > network
> > interface up or down). Your kernel .config would be useful as well.
>
> Stefan, could you provide the data Vinicius asked for? Or did you do
> that in private already? Or was progress made somewhere else and I
> simply missed this?
>
> Ciao, Thorsten, your Linux kernel regression tracker.
>
> P.S.: As a Linux kernel regression tracker I'm getting a lot of
> reports
> on my table. I can only look briefly into most of them. Unfortunately
> therefore I sometimes will get things wrong or miss something
> important.
> I hope that's not the case here; if you think it is, don't hesitate
> to
> tell me about it in a public reply. That's in everyone's interest, as
> what I wrote above might be misleading to everyone reading this; any
> suggestion I gave they thus might sent someone reading this down the
> wrong rabbit hole, which none of us wants.
>
> BTW, I have no personal interest in this issue, which is tracked
> using
> regzbot, my Linux kernel regression tracking bot
> (https://linux-regtracking.leemhuis.info/regzbot/). I'm only posting
> this mail to get things rolling again and hence don't need to be CC
> on
> all further activities wrt to this regression.
>
> #regzbot poke
>
> > > On Wed, 2021-12-01 at 10:57 -0800, Vinicius Costa Gomes wrote:
> > > > Inspired by:
> > > > https://bugzilla.kernel.org/show_bug.cgi?id=215129
> > > >
> > > > Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> > > > ---
> > > > Just to see if it's indeed the same problem as the bug report
> > > > above.
> > > >
> > > >  drivers/net/ethernet/intel/igc/igc_main.c | 19 +++++++++++++
> > > > ------
> > > >  1 file changed, 13 insertions(+), 6 deletions(-)
> > > >
> > > > diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
> > > > b/drivers/net/ethernet/intel/igc/igc_main.c
> > > > index 0e19b4d02e62..c58bf557a2a1 100644
> > > > --- a/drivers/net/ethernet/intel/igc/igc_main.c
> > > > +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> > > > @@ -6619,7 +6619,7 @@ static void
> > > > igc_deliver_wake_packet(struct
> > > > net_device *netdev)
> > > >  	netif_rx(skb);
> > > >  }
> > > >
> > > > -static int __maybe_unused igc_resume(struct device *dev)
> > > > +static int __maybe_unused __igc_resume(struct device *dev,
> > > > bool rpm)
> > > >  {
> > > >  	struct pci_dev *pdev = to_pci_dev(dev);
> > > >  	struct net_device *netdev = pci_get_drvdata(pdev);
> > > > @@ -6661,20 +6661,27 @@ static int __maybe_unused
> > > > igc_resume(struct
> > > > device *dev)
> > > >
> > > >  	wr32(IGC_WUS, ~0);
> > > >
> > > > -	rtnl_lock();
> > > > +	if (!rpm)
> > > > +		rtnl_lock();
> > > >  	if (!err && netif_running(netdev))
> > > >  		err = __igc_open(netdev, true);
> > > >
> > > >  	if (!err)
> > > >  		netif_device_attach(netdev);
> > > > -	rtnl_unlock();
> > > > +	if (!rpm)
> > > > +		rtnl_unlock();
> > > >
> > > >  	return err;
> > > >  }
> > > >
> > > >  static int __maybe_unused igc_runtime_resume(struct device
> > > > *dev)
> > > >  {
> > > > -	return igc_resume(dev);
> > > > +	return __igc_resume(dev, true);
> > > > +}
> > > > +
> > > > +static int __maybe_unused igc_resume(struct device *dev)
> > > > +{
> > > > +	return __igc_resume(dev, false);
> > > >  }
> > > >
> > > >  static int __maybe_unused igc_suspend(struct device *dev)
> > > > @@ -6738,7 +6745,7 @@ static pci_ers_result_t
> > > > igc_io_error_detected(struct pci_dev *pdev,
> > > >   *  @pdev: Pointer to PCI device
> > > >   *
> > > >   *  Restart the card from scratch, as if from a cold-boot.
> > > > Implementation
> > > > - *  resembles the first-half of the igc_resume routine.
> > > > + *  resembles the first-half of the __igc_resume routine.
> > > >   **/
> > > >  static pci_ers_result_t igc_io_slot_reset(struct pci_dev
> > > > *pdev)
> > > >  {
> > > > @@ -6777,7 +6784,7 @@ static pci_ers_result_t
> > > > igc_io_slot_reset(struct pci_dev *pdev)
> > > >   *
> > > >   *  This callback is called when the error recovery driver
> > > > tells us
> > > > that
> > > >   *  its OK to resume normal operation. Implementation
> > > > resembles the
> > > > - *  second-half of the igc_resume routine.
> > > > + *  second-half of the __igc_resume routine.
> > > >   */
> > > >  static void igc_io_resume(struct pci_dev *pdev)
> > > >  {
> >
> > Cheers,
> >