V4L/DVB (13132): fix use-after-free Oops, resulting from a driver-core API change

Commit b4028437876866aba4747a655ede00f892089e14 has broken again re-use of
device objects across device_register() / device_unregister() cycles. Fix
soc-camera by nullifying the struct after device_unregister().

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 9 insertions, 7 deletions

diff --git a/drivers/media/video/soc_camera.c b/drivers/media/video/soc_camera.c
index 59aa7a3694c..36e617bd13c 100644
--- a/drivers/media/video/soc_camera.c
+++ b/drivers/media/video/soc_camera.c
@@ -1160,13 +1160,15 @@ void soc_camera_host_unregister(struct soc_camera_host *ici)
                 if (icd->iface == ici->nr) {
                         /* The bus->remove will be called */
                         device_unregister(&icd->dev);
-                        /* Not before device_unregister(), .remove
-                         * needs parent to call ici->ops->remove() */
-                        icd->dev.parent = NULL;
-
-                        /* If the host module is loaded again, device_register()
-                         * would complain "already initialised" */
-                        memset(&icd->dev.kobj, 0, sizeof(icd->dev.kobj));
+                        /*
+                         * Not before device_unregister(), .remove
+                         * needs parent to call ici->ops->remove().
+                         * If the host module is loaded again, device_register()
+                         * would complain "already initialised," since 2.6.32
+                         * this is also needed to prevent use-after-free of the
+                         * device private data.
+                         */
+                        memset(&icd->dev, 0, sizeof(icd->dev));
                 }
         }