diff options
| author | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2019-12-08 01:48:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-09 12:19:00 +0300 |
| commit | cdcf9c99212e4d8b89101f2492963db5b3d0463e (patch) | |
| tree | 78cf00ca1df88e67a496ed40595003e4bae68656 | |
| parent | ffbcee5097adf4f5029f0c44e45bce96148180c7 (diff) | |
| download | linux-cdcf9c99212e4d8b89101f2492963db5b3d0463e.tar.xz | |
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: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org> # for v4.12 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/media/cec/cec-adap.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c index 913b3ff6c7bc..16f2181ec983 100644 --- a/drivers/media/cec/cec-adap.c +++ b/drivers/media/cec/cec-adap.c @@ -365,7 +365,8 @@ 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)) - data->adap->transmit_queue_sz--; + if (!WARN_ON(!data->adap->transmit_queue_sz)) + data->adap->transmit_queue_sz--; } if (data->msg.tx_status & CEC_TX_STATUS_OK) { @@ -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; } /* @@ -507,7 +516,8 @@ int cec_thread_func(void *_adap) data = list_first_entry(&adap->transmit_queue, struct cec_data, list); list_del_init(&data->list); - adap->transmit_queue_sz--; + if (!WARN_ON(!data->adap->transmit_queue_sz)) + adap->transmit_queue_sz--; /* Make this the current transmitting message */ adap->transmitting = data; |