[PATCH] ata: sata_mv: check for errors when parsing nr-ports from dt

[PATCH] ata: sata_mv: check for errors when parsing nr-ports from dt

[Uwe Kleine-König]

If the nr-ports property is missing ata_host_alloc_pinfo is called with
n_ports = 0. This results in host->ports[0] = NULL which later makes
mv_init_host() oops when dereferencing this pointer.

Instead be a bit more cooperative and fail the probing with an error
message.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/ata/sata_mv.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index efc48bf89d51..823e938c9a78 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -4090,7 +4090,20 @@ static int mv_platform_probe(struct platform_device *pdev)
 
 	/* allocate host */
 	if (pdev->dev.of_node) {
-		of_property_read_u32(pdev->dev.of_node, "nr-ports", &n_ports);
+		rc = of_property_read_u32(pdev->dev.of_node, "nr-ports",
+					   &n_ports);
+		if (rc) {
+			dev_err(&pdev->dev,
+				"error parsing nr-ports property: %d\n", rc);
+			return rc;
+		}
+
+		if (n_ports <= 0) {
+			dev_err(&pdev->dev, "nr-ports must be positive: %d\n",
+				n_ports);
+			return -EINVAL;
+		}
+
 		irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
 	} else {
 		mv_platform_data = dev_get_platdata(&pdev->dev);
-- 
2.10.2

Re: [PATCH] ata: sata_mv: check for errors when parsing nr-ports from dt

[Tejun Heo]

On Tue, Nov 29, 2016 at 12:13:38PM +0100, Uwe Kleine-König wrote:
> If the nr-ports property is missing ata_host_alloc_pinfo is called with
> n_ports = 0. This results in host->ports[0] = NULL which later makes
> mv_init_host() oops when dereferencing this pointer.
> 
> Instead be a bit more cooperative and fail the probing with an error
> message.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Applied to libata/for-4.9-fixes.

Thanks.

-- 
tejun