s390/pci: Fix leak of struct zpci_dev when zpci_add_device() fails

Prior to commit 0467cdde8c43 ("s390/pci: Sort PCI functions prior to
creating virtual busses") the IOMMU was initialized and the device was
registered as part of zpci_create_device() with the struct zpci_dev
freed if either resulted in an error. With that commit this was moved
into a separate function called zpci_add_device().

While this new function logs when adding failed, it expects the caller
not to use and to free the struct zpci_dev on error. This difference
between it and zpci_create_device() was missed while changing the
callers and the incompletely initialized struct zpci_dev may get used in
zpci_scan_configured_device in the error path. This then leads to
a crash due to the device not being registered with the zbus. It was
also not freed in this case. Fix this by handling the error return of
zpci_add_device(). Since in this case the zdev was not added to the
zpci_list it can simply be discarded and freed. Also make this more
explicit by moving the kref_init() into zpci_add_device() and document
that zpci_zdev_get()/zpci_zdev_put() must be used after adding.

Cc: stable@vger.kernel.org
Fixes: 0467cdde8c43 ("s390/pci: Sort PCI functions prior to creating virtual busses")
Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index 47f934f4e828..7f7b732b3f3e 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -340,7 +340,10 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED);
 			if (IS_ERR(zdev))
 				break;
-			zpci_add_device(zdev);
+			if (zpci_add_device(zdev)) {
+				kfree(zdev);
+				break;
+			}
 		} else {
 			/* the configuration request may be stale */
 			if (zdev->state != ZPCI_FN_STATE_STANDBY)
@@ -354,7 +357,10 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY);
 			if (IS_ERR(zdev))
 				break;
-			zpci_add_device(zdev);
+			if (zpci_add_device(zdev)) {
+				kfree(zdev);
+				break;
+			}
 		} else {
 			zpci_update_fh(zdev, ccdf->fh);
 		}