From e7cd17a29d72868aa5cfbbd4de7c54a28ed30ff0 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Tue, 9 Aug 2016 18:33:03 -0300
Subject: [PATCH] [media] drivers/media/media-device: fix double free bug in
_unregister()
While removing all interfaces in media_device_unregister(), all
media_interface pointers are freed. This is illegal and results in
double kfree() if any media_interface is still linked at this point;
maybe because a userspace process still has a file handle. Once the
process closes the file handle, dvb_media_device_free() gets called,
which frees the dvb_device.intf_devnode again.
This patch removes the unnecessary kfree() call, and documents who's
responsible for really freeing it.
Signed-off-by: Max Kellermann <max.kellermann@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
drivers/media/media-device.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 2783531f9fc01..219ab5fc8b4c0 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -801,9 +801,13 @@ void media_device_unregister(struct media_device *mdev)
/* Remove all interfaces from the media device */
list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
graph_obj.list) {
+ /*
+ * Unlink the interface, but don't free it here; the
+ * module which created it is responsible for freeing
+ * it
+ */
__media_remove_intf_links(intf);
media_gobj_destroy(&intf->graph_obj);
- kfree(intf);
}
mutex_unlock(&mdev->graph_mutex);
--
2.30.2