Merge tag 's390-5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fix from Vasily Gorbik:

 - fix use after free of zpci_dev in pci code

* tag 's390-5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/pci: fix use after free of zpci_dev

Author: torvalds

arch/s390/pci/pci.c

@@ -560,9 +560,12 @@ static void zpci_cleanup_bus_resources(struct zpci_dev *zdev)
 
 int pcibios_add_device(struct pci_dev *pdev)
 {
+	struct zpci_dev *zdev = to_zpci(pdev);
 	struct resource *res;
 	int i;
 
+	/* The pdev has a reference to the zdev via its bus */
+	zpci_zdev_get(zdev);
 	if (pdev->is_physfn)
 		pdev->no_vf_scan = 1;
 
@@ -582,7 +585,10 @@ int pcibios_add_device(struct pci_dev *pdev)
 
 void pcibios_release_device(struct pci_dev *pdev)
 {
+	struct zpci_dev *zdev = to_zpci(pdev);
+
 	zpci_unmap_resources(pdev);
+	zpci_zdev_put(zdev);
 }
 
 int pcibios_enable_device(struct pci_dev *pdev, int mask)

arch/s390/pci/pci_bus.h

@@ -22,6 +22,11 @@ static inline void zpci_zdev_put(struct zpci_dev *zdev)
 	kref_put(&zdev->kref, zpci_release_device);
 }
 
+static inline void zpci_zdev_get(struct zpci_dev *zdev)
+{
+	kref_get(&zdev->kref);
+}
+
 int zpci_alloc_domain(int domain);
 void zpci_free_domain(int domain);
 int zpci_setup_bus_resources(struct zpci_dev *zdev,