linux-kernel - [PATCH] PCI: Prevent NULL dereference during pciehp probe

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Message-Id: <1402347812-8059-1-git-send-email-andreas.noever@gmail.com>
Date:	Mon,  9 Jun 2014 23:03:32 +0200
From:	Andreas Noever <andreas.noever@...il.com>
To:	linux-kernel@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
	linux-pci@...r.kernel.org
Cc:	Andreas Noever <andreas.noever@...il.com>
Subject: [PATCH] PCI: Prevent NULL dereference during pciehp probe

pciehp assumes that dev->subordinate exists. But we do not assign a bus
if we run out of bus numbers during enumeration. This leads to a NULL
dereference in init_slot (and other places).

Change pciehp_probe to return -ENODEV when no subordinate bus is
present.

Signed-off-by: Andreas Noever <andreas.noever@...il.com>
---
 drivers/pci/hotplug/pciehp_core.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 0e0a2ff..e5abcaf 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -255,6 +255,13 @@ static int pciehp_probe(struct pcie_device *dev)
 	else if (pciehp_acpi_slot_detection_check(dev->port))
 		goto err_out_none;
 
+	if (!dev->port->subordinate) {
+		/* Can happen if we run out of bus numbers during probe */
+		dev_err(&dev->device,
+			"Hotplug bridge without secondary bus, ignoring\n");
+		goto err_out_none;
+	}
+
 	ctrl = pcie_init(dev);
 	if (!ctrl) {
 		dev_err(&dev->device, "Controller initialization failed\n");
-- 
2.0.0

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