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authorMike Qiu <qiudayu@linux.vnet.ibm.com>2014-04-14 16:12:35 -0600
committerBjorn Helgaas <bhelgaas@google.com>2014-04-14 16:33:49 -0600
commit140ab6452c42174d20e2fdd27ed73b889cd86500 (patch)
tree6cc7d886506931f27419040efd98e096508fb501 /arch/powerpc/kernel/pci_64.c
parentc9eaa447e77efe77b7fa4c953bd62de8297fd6c5 (diff)
powerpc/PCI: Fix NULL dereference in sys_pciconfig_iobase() list traversal
3bc955987fb3 ("powerpc/PCI: Use list_for_each_entry() for bus traversal") caused a NULL pointer dereference because the loop body set the iterator to NULL: Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc000000000041d78 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c000000000041d78] .sys_pciconfig_iobase+0x68/0x1f0 LR [c000000000041e0c] .sys_pciconfig_iobase+0xfc/0x1f0 Call Trace: [c0000003b4787db0] [c000000000041e0c] .sys_pciconfig_iobase+0xfc/0x1f0 (unreliable) [c0000003b4787e30] [c000000000009ed8] syscall_exit+0x0/0x98 Fix it by using a temporary variable for the iterator. [bhelgaas: changelog, drop tmp_bus initialization] Fixes: 3bc955987fb3 powerpc/PCI: Use list_for_each_entry() for bus traversal Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'arch/powerpc/kernel/pci_64.c')
-rw-r--r--arch/powerpc/kernel/pci_64.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index 2a4779091a58..155013da27e0 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -208,7 +208,7 @@ long sys_pciconfig_iobase(long which, unsigned long in_bus,
unsigned long in_devfn)
{
struct pci_controller* hose;
- struct pci_bus *bus = NULL;
+ struct pci_bus *tmp_bus, *bus = NULL;
struct device_node *hose_node;
/* Argh ! Please forgive me for that hack, but that's the
@@ -229,10 +229,12 @@ long sys_pciconfig_iobase(long which, unsigned long in_bus,
* used on pre-domains setup. We return the first match
*/
- list_for_each_entry(bus, &pci_root_buses, node) {
- if (in_bus >= bus->number && in_bus <= bus->busn_res.end)
+ list_for_each_entry(tmp_bus, &pci_root_buses, node) {
+ if (in_bus >= tmp_bus->number &&
+ in_bus <= tmp_bus->busn_res.end) {
+ bus = tmp_bus;
break;
- bus = NULL;
+ }
}
if (bus == NULL || bus->dev.of_node == NULL)
return -ENODEV;