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| author | Mike Qiu <qiudayu@linux.vnet.ibm.com> | 2014-04-15 00:12:35 +0200 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2014-04-15 00:33:49 +0200 |
| commit | 140ab6452c42174d20e2fdd27ed73b889cd86500 (patch) | |
| tree | 6cc7d886506931f27419040efd98e096508fb501 /arch/powerpc/kernel/pci_64.c | |
| parent | Linux 3.15-rc1 (diff) | |
| download | linux-140ab6452c42174d20e2fdd27ed73b889cd86500.tar.xz linux-140ab6452c42174d20e2fdd27ed73b889cd86500.zip | |
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.c | 10 |
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; |