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authorKrzysztof =?utf-8?Q?Ha=C5=82asa?= <khalasa@piap.pl>2016-03-01 07:07:18 +0100
committerBjorn Helgaas <bhelgaas@google.com>2016-03-07 14:33:16 -0600
commit54c6e2dd00c313d0add58e5befe62fe6f286d03b (patch)
tree611c861874b61a1829f2db393e1f9af8f754f9e0 /drivers/pci/pci.c
parent1195c103f6c98d9ff381cac3a8760d4f8a133627 (diff)
downloadlinux-54c6e2dd00c313d0add58e5befe62fe6f286d03b.tar.bz2
PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr()
pci_create_root_bus() passes a "parent" pointer to pci_bus_assign_domain_nr(). When CONFIG_PCI_DOMAINS_GENERIC is defined, pci_bus_assign_domain_nr() dereferences that pointer. Many callers of pci_create_root_bus() supply a NULL "parent" pointer, which leads to a NULL pointer dereference error. 7c674700098c ("PCI: Move domain assignment from arm64 to generic code") moved the "parent" dereference from arm64 to generic code. Only arm64 used that code (because only arm64 defined CONFIG_PCI_DOMAINS_GENERIC), and it always supplied a valid "parent" pointer. Other arches supplied NULL "parent" pointers but didn't defined CONFIG_PCI_DOMAINS_GENERIC, so they used a no-op version of pci_bus_assign_domain_nr(). 8c7d14746abc ("ARM/PCI: Move to generic PCI domains") defined CONFIG_PCI_DOMAINS_GENERIC on ARM, and many ARM platforms use pci_common_init(), which supplies a NULL "parent" pointer. These platforms (cns3xxx, dove, footbridge, iop13xx, etc.) crash with a NULL pointer dereference like this while probing PCI: Unable to handle kernel NULL pointer dereference at virtual address 000000a4 PC is at pci_bus_assign_domain_nr+0x10/0x84 LR is at pci_create_root_bus+0x48/0x2e4 Kernel panic - not syncing: Attempted to kill init! [bhelgaas: changelog, add "Reported:" and "Fixes:" tags] Reported: http://forum.doozan.com/read.php?2,17868,22070,quote=1 Fixes: 8c7d14746abc ("ARM/PCI: Move to generic PCI domains") Fixes: 7c674700098c ("PCI: Move domain assignment from arm64 to generic code") Signed-off-by: Krzysztof HaƂasa <khalasa@piap.pl> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> CC: stable@vger.kernel.org # v4.0+
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r--drivers/pci/pci.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 602eb4223510..f89db3af0607 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4772,8 +4772,10 @@ int pci_get_new_domain_nr(void)
void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
{
static int use_dt_domains = -1;
- int domain = of_get_pci_domain_nr(parent->of_node);
+ int domain = -1;
+ if (parent)
+ domain = of_get_pci_domain_nr(parent->of_node);
/*
* Check DT domain and use_dt_domains values.
*