[GIT PULL] s390 updates for 5.14-rc7

[Vasily Gorbik]

Hello Linus,

please pull s390 fix for 5.14-rc7.

Thank you,
Vasily

The following changes since commit 7c60610d476766e128cc4284bb6349732cbd6606:

  Linux 5.14-rc6 (2021-08-15 13:40:53 -1000)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git tags/s390-5.14-5

for you to fetch changes up to 2a671f77ee49f3e78997b77fdee139467ff6a598:

  s390/pci: fix use after free of zpci_dev (2021-08-18 10:12:42 +0200)

----------------------------------------------------------------
s390 updates for 5.14-rc7

- fix use after free of zpci_dev in pci code

----------------------------------------------------------------
Niklas Schnelle (1):
      s390/pci: fix use after free of zpci_dev

 arch/s390/pci/pci.c     | 6 ++++++
 arch/s390/pci/pci_bus.h | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index b0993e05affe..8fcb7ecb7225 100644
--- a/arch/s390/pci/pci.c
+++ b/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)
diff --git a/arch/s390/pci/pci_bus.h b/arch/s390/pci/pci_bus.h
index b877a97e6745..e359d2686178 100644
--- a/arch/s390/pci/pci_bus.h
+++ b/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,