From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zhang Subject: [PATCH 1/1] net/e1000e: Avoid kernel crash during shutdown Date: Tue, 13 Aug 2013 14:27:07 +0800 Message-ID: <1376375227-24274-1-git-send-email-zhlcindy@gmail.com> Cc: shangw@linux.vnet.ibm.com To: jeffrey.t.kirsher@intel.com, jesse.brandeburg@intel.com, davem@davemloft.net, netdev@vger.kernel.org Return-path: Received: from mail-pd0-f181.google.com ([209.85.192.181]:65183 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755438Ab3HMG1e (ORCPT ); Tue, 13 Aug 2013 02:27:34 -0400 Received: by mail-pd0-f181.google.com with SMTP id g10so4417546pdj.40 for ; Mon, 12 Aug 2013 23:27:33 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: 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 --- 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 77f81cb..232b2e8 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)); -- 1.8.1.4