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[2001:b011:380f:3214:6d62:6b9e:e5b8:db59]) by smtp.gmail.com with ESMTPSA id e18sm16697476pfm.24.2020.02.25.01.42.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 25 Feb 2020 01:42:30 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.60.0.2.5\)) Subject: Re: [RFC PATCH v2] e1000e: Use rtnl_lock to prevent race conditions between net and pci/pm From: Kai-Heng Feng In-Reply-To: <20191007172559.11166.29328.stgit@localhost.localdomain> Date: Tue, 25 Feb 2020 17:42:26 +0800 Cc: Alexander Duyck , zdai@linux.vnet.ibm.com, "open list:NETWORKING DRIVERS" , open list , "moderated list:INTEL ETHERNET DRIVERS" , "Kirsher, Jeffrey T" , zdai@us.ibm.com, David Miller Content-Transfer-Encoding: 8BIT Message-Id: <681404C7-9015-4C64-B8FE-2C93D75A7318@canonical.com> References: <20191007172559.11166.29328.stgit@localhost.localdomain> To: Greg Kroah-Hartman , stable X-Mailer: Apple Mail (2.3608.60.0.2.5) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Greg, > On Oct 8, 2019, at 01:27, Alexander Duyck wrote: > > From: Alexander Duyck > > 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 Please merge this commit, a7023819404ac9bd2bb311a4fafd38515cfa71ec to stable v5.14. `modprobe -r e1000e` triggers a null pointer dereference [1] after the the following two patches are applied to v5.4.y: d635e7c4b34e6a630c7a1e8f1a8fd52c3e3ceea7 e1000e: Revert "e1000e: Make watchdog use delayed work" 21c6137939723ed6f5e4aec7882cdfc247304c27 e1000e: Drop unnecessary __E1000_DOWN bit twiddling [1] https://bugs.launchpad.net/bugs/1864303 Kai-Heng > --- > > RFC v2: Dropped some unused variables > Added logic to check for device present before removing to pm_freeze > Fixed misplaced err_irq to before rtnl_unlock() > > drivers/net/ethernet/intel/e1000e/netdev.c | 40 +++++++++++++++------------- > 1 file changed, 21 insertions(+), 19 deletions(-) > > diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c > index d7d56e42a6aa..8b4e589aca36 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); > @@ -6298,10 +6298,14 @@ static int e1000e_pm_freeze(struct device *dev) > { > struct net_device *netdev = dev_get_drvdata(dev); > struct e1000_adapter *adapter = netdev_priv(netdev); > + bool present; > > + rtnl_lock(); > + > + present = netif_device_present(netdev); > netif_device_detach(netdev); > > - if (netif_running(netdev)) { > + if (present && netif_running(netdev)) { > int count = E1000_CHECK_RESET_COUNT; > > while (test_bit(__E1000_RESETTING, &adapter->state) && count--) > @@ -6313,6 +6317,8 @@ 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 +6632,31 @@ 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); > +err_irq: > + rtnl_unlock(); > > - return 0; > + return rc; > } > > +#ifdef CONFIG_PM_SLEEP > static int e1000e_pm_suspend(struct device *dev) > { > struct pci_dev *pdev = to_pci_dev(dev); > @@ -6818,16 +6828,11 @@ static void e1000_netpoll(struct net_device *netdev) > static pci_ers_result_t e1000_io_error_detected(struct pci_dev *pdev, > pci_channel_state_t state) > { > - 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 +6898,7 @@ 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 >