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

[ Upstream commit 7f404ae9cf ]

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>
5.4-rM2-2.2.x-imx-squashed
Mike Isely 2019-11-06 12:11:14 +01:00 committed by Greg Kroah-Hartman
parent 347d4a868c
commit 570cacc74e
1 changed files with 7 additions and 2 deletions
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9
drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
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@ -898,8 +898,12 @@ 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);
}
@ -935,7 +939,8 @@ 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;