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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-10-01 15:58:10 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-10-07 18:42:44 +0200
commit3fb937f441c64af1eec60bfd3732f64001fcc534 (patch)
treecf4bcd87010d4ef093f8aeb07ffd527b5a89bc5b /drivers
parent9e1ff307c779ce1f0f810c7ecce3d95bbae40896 (diff)
PCI: ACPI: Check parent pointer in acpi_pci_find_companion()
If acpi_pci_find_companion() is called for a device whose parent pointer is NULL, it will crash when attempting to get the ACPI companion of the parent due to a NULL pointer dereference in the ACPI_COMPANION() macro. This was not a problem before commit 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time with OF") that made pci_setup_device() call pci_set_acpi_fwnode() and so it allowed devices with NULL parent pointers to be passed to acpi_pci_find_companion() which is the case in pci_iov_add_virtfn(), for instance. Fix this issue by making acpi_pci_find_companion() check the device's parent pointer upfront and bail out if it is NULL. While pci_iov_add_virtfn() can be changed to set the device's parent pointer before calling pci_setup_device() for it, checking pointers against NULL before dereferencing them is prudent anyway and looking for ACPI companions of virtual functions isn't really useful. Fixes: 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time with OF") Link: https://lore.kernel.org/linux-acpi/8e4bbd5c59de31db71f718556654c0aa077df03d.camel@linux.ibm.com/ Reported-by: Niklas Schnelle <schnelle@linux.ibm.com> Tested-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pci-acpi.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 0f40943a9a18..260a06fb78a6 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1249,6 +1249,9 @@ static struct acpi_device *acpi_pci_find_companion(struct device *dev)
bool check_children;
u64 addr;
+ if (!dev->parent)
+ return NULL;
+
down_read(&pci_acpi_companion_lookup_sem);
adev = pci_acpi_find_companion_hook ?