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Subject[PATCH 6/6] drivers/media/dvb-usb-dvb: postpone kfree(mdev)
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Date
Fixes use-after-free bug which occurs when I disconnect my DVB-S
received while VDR is running.

Signed-off-by: Max Kellermann <max@duempel.org>
---
drivers/media/usb/dvb-usb/dvb-usb-dvb.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-dvb.c b/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
index 9ddfcab..7859479 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
@@ -95,6 +95,12 @@ static int dvb_usb_stop_feed(struct dvb_demux_feed *dvbdmxfeed)
return dvb_usb_ctrl_feed(dvbdmxfeed, 0);
}

+static void dvb_usb_media_device_release(struct media_device *mdev)
+{
+ media_device_cleanup(mdev);
+ kfree(mdev);
+}
+
static int dvb_usb_media_device_init(struct dvb_usb_adapter *adap)
{
#ifdef CONFIG_MEDIA_CONTROLLER_DVB
@@ -113,6 +119,7 @@ static int dvb_usb_media_device_init(struct dvb_usb_adapter *adap)
strcpy(mdev->bus_info, udev->devpath);
mdev->hw_revision = le16_to_cpu(udev->descriptor.bcdDevice);
mdev->driver_version = LINUX_VERSION_CODE;
+ mdev->release = dvb_usb_media_device_release;

media_device_init(mdev);

@@ -138,10 +145,11 @@ static void dvb_usb_media_device_unregister(struct dvb_usb_adapter *adap)
if (!adap->dvb_adap.mdev)
return;

- media_device_unregister(adap->dvb_adap.mdev);
- media_device_cleanup(adap->dvb_adap.mdev);
- kfree(adap->dvb_adap.mdev);
+ struct media_device *mdev = adap->dvb_adap.mdev;
adap->dvb_adap.mdev = NULL;
+ media_device_unregister(mdev);
+ /* media_device_cleanup() and kfree() will be called by the
+ callback function dvb_usb_media_device_release() */
#endif
}

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