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Commit cdcf9c99 authored by Hans Verkuil's avatar Hans Verkuil Committed by Greg Kroah-Hartman
Browse files

media: cec: avoid decrementing transmit_queue_sz if it is 0 



commit 95c29d46ab2a517e4c26d0a07300edca6768db17 upstream.

WARN if transmit_queue_sz is 0 but do not decrement it.
The CEC adapter will become unresponsive if it goes below
0 since then it thinks there are 4 billion messages in the
queue.

Obviously this should not happen, but a driver bug could
cause this.

Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org>      # for v4.12 and up
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ffbcee50

drivers/media/cec/cec-adap.c

+12 −2
Original line number Diff line number Diff line
@@ -365,6 +365,7 @@ static void cec_data_cancel(struct cec_data *data, u8 tx_status) 
	} else {

		list_del_init(&data->list);

		if (!(data->msg.tx_status & CEC_TX_STATUS_OK))

			if (!WARN_ON(!data->adap->transmit_queue_sz))

				data->adap->transmit_queue_sz--;

	}
@@ -417,6 +418,14 @@ static void cec_flush(struct cec_adapter *adap) 
		 * need to do anything special in that case.

		 */

	}

	/*

	 * If something went wrong and this counter isn't what it should

	 * be, then this will reset it back to 0. Warn if it is not 0,

	 * since it indicates a bug, either in this framework or in a

	 * CEC driver.

	 */

	if (WARN_ON(adap->transmit_queue_sz))

		adap->transmit_queue_sz = 0;

}



/*
@@ -507,6 +516,7 @@ int cec_thread_func(void *_adap) 
		data = list_first_entry(&adap->transmit_queue,

					struct cec_data, list);

		list_del_init(&data->list);

		if (!WARN_ON(!data->adap->transmit_queue_sz))

			adap->transmit_queue_sz--;



		/* Make this the current transmitting message */