From: Jesper Juhl Date: Mon, 24 Jan 2011 20:14:33 +0000 (+0100) Subject: PCI: Avoid potential NULL pointer dereference in pci_scan_bridge X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=7c867c8899e873652ef98a890d2e647c092bec25;p=openwrt%2Fstaging%2Fblogic.git PCI: Avoid potential NULL pointer dereference in pci_scan_bridge pci_add_new_bus() calls pci_alloc_child_bus() which calls pci_alloc_bus() that allocates memory dynamically with kzalloc(). The return value of kzalloc() is the pointer that's eventually returned from pci_add_new_bus(), so since kzalloc() can fail and return NULL so can pci_add_new_bus(). Thus we may end up dereferencing a NULL pointer in drivers/pci/probe.c::pci_scan_bridge(). Seems to me we should test for this and bail out if it happens rather than crashing. Also removed some trailing whitespace that bugged me while looking at this. Signed-off-by: Jesper Juhl Signed-off-by: Jesse Barnes --- diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index c84900da3c59..44cbbbaa499d 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -764,6 +764,8 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, if (pci_find_bus(pci_domain_nr(bus), max+1)) goto out; child = pci_add_new_bus(bus, dev, ++max); + if (!child) + goto out; buses = (buses & 0xff000000) | ((unsigned int)(child->primary) << 0) | ((unsigned int)(child->secondary) << 8) @@ -777,7 +779,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, buses &= ~0xff000000; buses |= CARDBUS_LATENCY_TIMER << 24; } - + /* * We need to blast all three values with a single write. */