Messages in this thread | | | Subject | Re: [RFC PATCH] e1000e: Use rtnl_lock to prevent race conditions between net and pci/pm | From | "David Z. Dai" <> | Date | Fri, 04 Oct 2019 21:18:46 -0500 |
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On Fri, 2019-10-04 at 16:36 -0700, Alexander Duyck wrote: > From: Alexander Duyck <alexander.h.duyck@linux.intel.com> > > This patch is meant to address possible race conditions that can exist > between network configuration and power management. A similar issue was > fixed for igb in commit 9474933caf21 ("igb: close/suspend race in > netif_device_detach"). > > In addition it consolidates the code so that the PCI error handling code > will essentially perform the power management freeze on the device prior to > attempting a reset, and will thaw the device afterwards if that is what it > is planning to do. Otherwise when we call close on the interface it should > see it is detached and not attempt to call the logic to down the interface > and free the IRQs again. > > >From what I can tell the check that was adding the check for __E1000_DOWN > in e1000e_close was added when runtime power management was added. However > it should not be relevant for us as we perform a call to > pm_runtime_get_sync before we call e1000_down/free_irq so it should always > be back up before we call into this anyway. > > Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> > --- > > I'm putting this out as an RFC for now. I haven't had a chance to do much > testing yet, but I have verified no build issues, and the driver appears > to load, link, and pass traffic without problems. > > This should address issues seen with either double freeing or never freeing > IRQs that have been seen on this and similar drivers in the past. > > I'll submit this formally after testing it over the weekend assuming there > are no issues. > > drivers/net/ethernet/intel/e1000e/netdev.c | 33 ++++++++++++++-------------- > 1 file changed, 17 insertions(+), 16 deletions(-) > > diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c > index d7d56e42a6aa..182a2c8f12d8 100644 > --- a/drivers/net/ethernet/intel/e1000e/netdev.c > +++ b/drivers/net/ethernet/intel/e1000e/netdev.c > @@ -4715,12 +4715,12 @@ int e1000e_close(struct net_device *netdev) > > pm_runtime_get_sync(&pdev->dev); > > - if (!test_bit(__E1000_DOWN, &adapter->state)) { > + if (netif_device_present(netdev)) { > e1000e_down(adapter, true); > e1000_free_irq(adapter); > > /* Link status message must follow this format */ > - pr_info("%s NIC Link is Down\n", adapter->netdev->name); > + pr_info("%s NIC Link is Down\n", netdev->name); > } > > napi_disable(&adapter->napi); > @@ -6299,6 +6299,7 @@ static int e1000e_pm_freeze(struct device *dev) > struct net_device *netdev = dev_get_drvdata(dev); > struct e1000_adapter *adapter = netdev_priv(netdev); > > + rtnl_lock(); > netif_device_detach(netdev); > > if (netif_running(netdev)) { > @@ -6313,6 +6314,8 @@ static int e1000e_pm_freeze(struct device *dev) > e1000e_down(adapter, false); > e1000_free_irq(adapter); > } > + rtnl_unlock(); > + > e1000e_reset_interrupt_capability(adapter); > > /* Allow time for pending master requests to run */ > @@ -6626,27 +6629,30 @@ static int __e1000_resume(struct pci_dev *pdev) > return 0; > } > > -#ifdef CONFIG_PM_SLEEP > static int e1000e_pm_thaw(struct device *dev) > { > struct net_device *netdev = dev_get_drvdata(dev); > struct e1000_adapter *adapter = netdev_priv(netdev); > + int rc = 0; > > e1000e_set_interrupt_capability(adapter); > - if (netif_running(netdev)) { > - u32 err = e1000_request_irq(adapter); > > - if (err) > - return err; > + rtnl_lock(); > + if (netif_running(netdev)) { > + rc = e1000_request_irq(adapter); > + if (rc) > + goto err_irq; > > e1000e_up(adapter); > } > > netif_device_attach(netdev); > - > - return 0; > + rtnl_unlock(); > +err_irq: > + return rc; > } > > +#ifdef CONFIG_PM_SLEEP > static int e1000e_pm_suspend(struct device *dev) > { > struct pci_dev *pdev = to_pci_dev(dev); > @@ -6821,13 +6827,11 @@ static pci_ers_result_t e1000_io_error_detected(struct pci_dev *pdev, > struct net_device *netdev = pci_get_drvdata(pdev); > struct e1000_adapter *adapter = netdev_priv(netdev); > > - netif_device_detach(netdev); > + e1000e_pm_freeze(&pdev->dev); > > if (state == pci_channel_io_perm_failure) > return PCI_ERS_RESULT_DISCONNECT; > > - if (netif_running(netdev)) > - e1000e_down(adapter, true); > pci_disable_device(pdev); > > /* Request a slot slot reset. */ > @@ -6893,10 +6897,7 @@ static void e1000_io_resume(struct pci_dev *pdev) > > e1000_init_manageability_pt(adapter); > > - if (netif_running(netdev)) > - e1000e_up(adapter); > - > - netif_device_attach(netdev); > + e1000e_pm_thaw(&pdev->dev); > > /* If the controller has AMT, do not set DRV_LOAD until the interface > * is up. For all other cases, let the f/w know that the h/w is now In e1000e_pm_thaw(), these 2 lines need to switch order to avoid deadlock. from: + rtnl_unlock(); +err_irq:
to: +err_irq: + rtnl_unlock();
I will find hardware to test this patch next week. Will update the test result later.
Thanks! - David
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