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Subject[PATCH 3/3] drivers/media/media-device: fix double free bug in _unregister()
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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@duempel.org>
---
drivers/media/media-device.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 33a9952..1db4707 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -799,9 +799,11 @@ 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);
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