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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-10-01 15:58:10 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-10-07 18:42:44 +0200 |
| commit | 3fb937f441c64af1eec60bfd3732f64001fcc534 (patch) | |
| tree | cf4bcd87010d4ef093f8aeb07ffd527b5a89bc5b | |
| parent | Linux 5.15-rc4 (diff) | |
| download | linux-3fb937f441c64af1eec60bfd3732f64001fcc534.tar.xz linux-3fb937f441c64af1eec60bfd3732f64001fcc534.zip | |
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>
| -rw-r--r-- | drivers/pci/pci-acpi.c | 3 |
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 ? |