Messages in this thread | | | Subject | Re: [PATCH 3/3] drivers/media/media-device: fix double free bug in _unregister() | From | Shuah Khan <> | Date | Wed, 15 Jun 2016 14:32:10 -0600 |
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On 06/15/2016 02:15 PM, Max Kellermann wrote: > 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);
This change introduces memory leaks, since drivers are relying on media_device_unregister() to free interfaces.
thanks, -- Shuah
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