netdev - [PATCH 1/1] net/e1000e: Avoid kernel crash during shutdown

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1376375227-24274-1-git-send-email-zhlcindy@gmail.com>
Date:	Tue, 13 Aug 2013 14:27:07 +0800
From:	Li Zhang <zhlcindy@...il.com>
To:	jeffrey.t.kirsher@...el.com, jesse.brandeburg@...el.com,
	davem@...emloft.net, netdev@...r.kernel.org
Cc:	shangw@...ux.vnet.ibm.com
Subject: [PATCH 1/1] net/e1000e: Avoid kernel crash during shutdown

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 <zhlcindy@...il.com>
---
 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

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html