diff options
| author | Krzysztof =?utf-8?Q?Ha=C5=82asa?= <khalasa@piap.pl> | 2016-03-01 07:07:18 +0100 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-03-07 14:33:16 -0600 |
| commit | 54c6e2dd00c313d0add58e5befe62fe6f286d03b (patch) | |
| tree | 611c861874b61a1829f2db393e1f9af8f754f9e0 /drivers/pci/pci.c | |
| parent | 1195c103f6c98d9ff381cac3a8760d4f8a133627 (diff) | |
| download | linux-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 Hałasa <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.c | 4 |
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. * |