From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 14/15] e1000e: Avoid kernel crash during shutdown Date: Wed, 21 Aug 2013 01:23:35 -0700 Message-ID: <1377073416-7872-15-git-send-email-jeffrey.t.kirsher@intel.com> References: <1377073416-7872-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Li Zhang , netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com, Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga14.intel.com ([143.182.124.37]:18759 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752021Ab3HUIYT (ORCPT ); Wed, 21 Aug 2013 04:24:19 -0400 In-Reply-To: <1377073416-7872-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Li Zhang While doing shutdown on the PCI device, the corresponding callback function e1000e_shutdown() is trying to clear those correctable errors on the upstream P2P bridge. Unfortunately, we don't have the upstream P2P bridge under some cases (e.g. PCI-passthrou for KVM on Power). That leads to kernel crash eventually. The patch adds one more check on that to avoid kernel crash. Signed-off-by: Li Zhang Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/e1000e/netdev.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 59c0c54..e87e9b0 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -5999,11 +5999,18 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool runtime) * correctable error when the MAC transitions from D0 to D3. To * prevent this we need to mask off the correctable errors on the * downstream port of the pci-e switch. + * + * We don't have the associated upstream bridge while assigning + * the PCI device into guest. For example, the KVM on power is + * one of the cases. */ if (adapter->flags & FLAG_IS_QUAD_PORT) { struct pci_dev *us_dev = pdev->bus->self; u16 devctl; + if (!us_dev) + return 0; + pcie_capability_read_word(us_dev, PCI_EXP_DEVCTL, &devctl); pcie_capability_write_word(us_dev, PCI_EXP_DEVCTL, (devctl & ~PCI_EXP_DEVCTL_CERE)); -- 1.8.3.1