Commit 3fd36843 authored Nov 06, 2019 by Mike Isely Committed by Greg Kroah-Hartman Dec 31, 2019

media: pvrusb2: Fix oops on tear-down when radio support is not present



[ Upstream commit 7f404ae9cf2a285f73b3c18ab9303d54b7a3d8e1 ]

In some device configurations there's no radio or radio support in the
driver.  That's OK, as the driver sets itself up accordingly.  However
on tear-down in these caes it's still trying to tear down radio
related context when there isn't anything there, leading to
dereferences through a null pointer and chaos follows.

How this bug survived unfixed for 11 years in the pvrusb2 driver is a
mystery to me.

[hverkuil: fix two checkpatch warnings]

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 7664c4a2

drivers/media/usb/pvrusb2/pvrusb2-v4l2.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -916,8 +916,12 @@ static void pvr2_v4l2_internal_check(struct pvr2_channel *chp)
		pvr2_v4l2_dev_disassociate_parent(vp->dev_video);
		pvr2_v4l2_dev_disassociate_parent(vp->dev_radio);
		if (!list_empty(&vp->dev_video->devbase.fh_list) \|\|
		!list_empty(&vp->dev_radio->devbase.fh_list))
		(vp->dev_radio &&
		!list_empty(&vp->dev_radio->devbase.fh_list))) {
		pvr2_trace(PVR2_TRACE_STRUCT,
		"pvr2_v4l2 internal_check exit-empty id=%p", vp);
		return;
		}
		pvr2_v4l2_destroy_no_lock(vp);
		}

		@@ -953,7 +957,8 @@ static int pvr2_v4l2_release(struct file *file)
		kfree(fhp);
		if (vp->channel.mc_head->disconnect_flag &&
		list_empty(&vp->dev_video->devbase.fh_list) &&
		list_empty(&vp->dev_radio->devbase.fh_list)) {
		(!vp->dev_radio \|\|
		list_empty(&vp->dev_radio->devbase.fh_list))) {
		pvr2_v4l2_destroy_no_lock(vp);
		}
		return 0;