[PATCH] msi001: fix possible null-ptr-deref in msi001_probe()

[Wang Hai]

I got a null-ptr-deref report:

BUG: kernel NULL pointer dereference, address: 0000000000000060
...
RIP: 0010:v4l2_ctrl_auto_cluster+0x57/0x270
...
Call Trace:
 msi001_probe+0x13b/0x24b [msi001]
 spi_probe+0xeb/0x130
...
 do_syscall_64+0x35/0xb0

In msi001_probe(), if the creation of control for bandwidth_auto
fails, there will be a null-ptr-deref issue when it is used in
v4l2_ctrl_auto_cluster().

Check dev->hdl.error before v4l2_ctrl_auto_cluster() to fix this bug.

Fixes: 93203dd6c7c4 ("[media] msi001: Mirics MSi001 silicon tuner driver")
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx>
---
 drivers/media/tuners/msi001.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/media/tuners/msi001.c b/drivers/media/tuners/msi001.c
index 78e6fd600d8e..44247049a319 100644
--- a/drivers/media/tuners/msi001.c
+++ b/drivers/media/tuners/msi001.c
@@ -442,6 +442,13 @@ static int msi001_probe(struct spi_device *spi)
 			V4L2_CID_RF_TUNER_BANDWIDTH_AUTO, 0, 1, 1, 1);
 	dev->bandwidth = v4l2_ctrl_new_std(&dev->hdl, &msi001_ctrl_ops,
 			V4L2_CID_RF_TUNER_BANDWIDTH, 200000, 8000000, 1, 200000);
+	if (dev->hdl.error) {
+		ret = dev->hdl.error;
+		dev_err(&spi->dev, "Could not initialize controls\n");
+		/* control init failed, free handler */
+		goto err_ctrl_handler_free;
+	}
+
 	v4l2_ctrl_auto_cluster(2, &dev->bandwidth_auto, 0, false);
 	dev->lna_gain = v4l2_ctrl_new_std(&dev->hdl, &msi001_ctrl_ops,
 			V4L2_CID_RF_TUNER_LNA_GAIN, 0, 1, 1, 1);
-- 
2.25.1