Merge tag 'acpi-5.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI fix from Rafael Wysocki:
 "Fix a recent ACPI-related regression in the PCI subsystem that
  introduced a NULL pointer dereference possible to trigger from
  user space via sysfs on some systems"

* tag 'acpi-5.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PCI: ACPI: Check parent pointer in acpi_pci_find_companion()

Author: torvalds

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 ?