| Message ID | 1427795008-10385-1-git-send-email-floe@butterbrot.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c index 1e7dacf..d618514 100644 --- a/drivers/input/touchscreen/sur40.c +++ b/drivers/input/touchscreen/sur40.c @@ -380,6 +380,11 @@ static void sur40_process_video(struct sur40_state *sur40) /* get a new buffer from the list */ spin_lock(&sur40->qlock); + if (list_empty(&sur40->buf_list)) { + dev_dbg(sur40->dev, "buffer queue empty\n"); + spin_unlock(&sur40->qlock); + return; + } new_buf = list_entry(sur40->buf_list.next, struct sur40_buffer, list); list_del(&new_buf->list); spin_unlock(&sur40->qlock);
This patch fixes a kernel panic which occurs when buf_list is empty. This can happen occasionally when user space is under heavy load (e.g. due to image processing on the CPU) and new buffers aren't re-queued fast enough. In that case, vb2_start_streaming_called can return true, but when the spinlock is taken and sur40_poll attempts to fetch the next buffer from buf_list, the list is in fact empty. This patch needs to be applied on top of the queued one adding V4L2 support to the sur40 driver. Signed-off-by: Florian Echtler <floe@butterbrot.org> --- drivers/input/touchscreen/sur40.c | 5 +++++ 1 file changed, 5 insertions(+)