From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Date: Tue, 29 Nov 2016 11:13:38 +0000 (+0100)
Subject: ata: sata_mv: check for errors when parsing nr-ports from dt
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5c3ef39738f74a3759918cc1a1ad099504f9d1b7;p=linux.git

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

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>
Signed-off-by: Tejun Heo <tj@kernel.org>
---

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index efc48bf89d518..823e938c9a787 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);