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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Malcolm Priestley <tvboxspy@gmail.com>,
        Sean Young <sean@mess.org>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Subject: [PATCH 4.20 045/145] media: dvb-usb-v2: Fix incorrect use of transfer_flags URB_FREE_BUFFER
Date:   Mon,  7 Jan 2019 13:31:22 +0100
Message-Id: <20190107104443.332815469@linuxfoundation.org>
In-Reply-To: <20190107104437.308206189@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Malcolm Priestley <tvboxspy@gmail.com>

commit 255095fa7f62ff09b6f61393414535c59c6b4cb0 upstream.

commit 1a0c10ed7bb1 ("media: dvb-usb-v2: stop using coherent memory for
URBs") incorrectly adds URB_FREE_BUFFER after every urb transfer.

It cannot use this flag because it reconfigures the URBs accordingly
to suit connected devices. In doing a call to usb_free_urb is made and
invertedly frees the buffers.

The stream buffer should remain constant while driver is up.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
CC: stable@vger.kernel.org # v4.18+
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/usb/dvb-usb-v2/usb_urb.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/media/usb/dvb-usb-v2/usb_urb.c
+++ b/drivers/media/usb/dvb-usb-v2/usb_urb.c
@@ -155,7 +155,6 @@ static int usb_urb_alloc_bulk_urbs(struc
 				stream->props.u.bulk.buffersize,
 				usb_urb_complete, stream);
 
-		stream->urb_list[i]->transfer_flags = URB_FREE_BUFFER;
 		stream->urbs_initialized++;
 	}
 	return 0;
@@ -186,7 +185,7 @@ static int usb_urb_alloc_isoc_urbs(struc
 		urb->complete = usb_urb_complete;
 		urb->pipe = usb_rcvisocpipe(stream->udev,
 				stream->props.endpoint);
-		urb->transfer_flags = URB_ISO_ASAP | URB_FREE_BUFFER;
+		urb->transfer_flags = URB_ISO_ASAP;
 		urb->interval = stream->props.u.isoc.interval;
 		urb->number_of_packets = stream->props.u.isoc.framesperurb;
 		urb->transfer_buffer_length = stream->props.u.isoc.framesize *
@@ -210,7 +209,7 @@ static int usb_free_stream_buffers(struc
 	if (stream->state & USB_STATE_URB_BUF) {
 		while (stream->buf_num) {
 			stream->buf_num--;
-			stream->buf_list[stream->buf_num] = NULL;
+			kfree(stream->buf_list[stream->buf_num]);
 		}
 	}