linux-kernel - [PATCH v3] mfd: tps6105x: Fix NULL pointer access.

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Date:	Mon, 21 Sep 2015 17:10:45 +0000
From:	Grigoryev Denis <grigoryev@...twel.ru>
To:	Lee Jones <lee.jones@...aro.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Samuel Ortiz" <sameo@...ux.intel.com>
Subject: [PATCH v3] mfd: tps6105x: Fix NULL pointer access.

When tps6105x used in TPS6105X_MODE_SHUTDOWN mode the driver calls
mfd_add_devices() with mfd_cell->name == NULL, that causes an ooops in
platform_device_register() later.

This patch adds an mfd_cell for each possible mode thereby excluding
.name assignment in runtime.

Signed-off-by: Denis Grigoryev <grigoryev@...twel.ru>
---
 drivers/mfd/tps6105x.c |   61 +++++++++++++++++++++++++++---------------------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/drivers/mfd/tps6105x.c b/drivers/mfd/tps6105x.c
index 5de95c2..6603fc8 100644
--- a/drivers/mfd/tps6105x.c
+++ b/drivers/mfd/tps6105x.c
@@ -119,17 +119,25 @@ static int tps6105x_startup(struct tps6105x *tps6105x)
 }
 
 /*
- * MFD cells - we have one cell which is selected operation
- * mode, and we always have a GPIO cell.
+ * MFD cells - we always have a GPIO cell and we have one cell
+ * which is selected operation mode.
  */
 static struct mfd_cell tps6105x_cells[] = {
-	{
-		/* name will be runtime assigned */
-		.id = -1,
+	[TPS6105X_MODE_SHUTDOWN]	= {
+		.name			= "tps6105x-gpio",
+		.id			= -1,
 	},
-	{
-		.name = "tps6105x-gpio",
-		.id = -1,
+	[TPS6105X_MODE_TORCH]		= {
+		.name			= "tps6105x-leds",
+		.id			= -1,
+	},
+	[TPS6105X_MODE_TORCH_FLASH]	= {
+		.name			= "tps6105x-flash",
+		.id			= -1,
+	},
+	[TPS6105X_MODE_VOLTAGE]		= {
+		.name			= "tps6105x-regulator",
+		.id			= -1,
 	},
 };
 
@@ -157,38 +165,39 @@ static int tps6105x_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	/* Remove warning texts when you implement new cell drivers */
+	/* Set up and register the platform devices. */
+	for (i = 0; i < ARRAY_SIZE(tps6105x_cells); i++) {
+		/* One state holder for all drivers, this is simple */
+		tps6105x_cells[i].platform_data = tps6105x;
+		tps6105x_cells[i].pdata_size = sizeof(*tps6105x);
+	}
+
+	ret = mfd_add_devices(&client->dev, -1, tps6105x_cells,
+			      1, NULL, 0, NULL);
+	if (ret)
+		return ret;
+
 	switch (pdata->mode) {
 	case TPS6105X_MODE_SHUTDOWN:
 		dev_info(&client->dev,
 			 "present, not used for anything, only GPIO\n");
 		break;
 	case TPS6105X_MODE_TORCH:
-		tps6105x_cells[0].name = "tps6105x-leds";
-		dev_warn(&client->dev,
-			 "torch mode is unsupported\n");
-		break;
 	case TPS6105X_MODE_TORCH_FLASH:
-		tps6105x_cells[0].name = "tps6105x-flash";
-		dev_warn(&client->dev,
-			 "flash mode is unsupported\n");
-		break;
 	case TPS6105X_MODE_VOLTAGE:
-		tps6105x_cells[0].name ="tps6105x-regulator";
+		ret = mfd_add_devices(&client->dev, -1,
+				      &tps6105x_cells[pdata->mode],
+				      1, NULL, 0, NULL);
 		break;
 	default:
+		dev_warn(&client->dev, "invalid mode: %d\n", pdata->mode);
 		break;
 	}
 
-	/* Set up and register the platform devices. */
-	for (i = 0; i < ARRAY_SIZE(tps6105x_cells); i++) {
-		/* One state holder for all drivers, this is simple */
-		tps6105x_cells[i].platform_data = tps6105x;
-		tps6105x_cells[i].pdata_size = sizeof(*tps6105x);
-	}
+	if (ret)
+		mfd_remove_devices(&client->dev);
 
-	return mfd_add_devices(&client->dev, 0, tps6105x_cells,
-			       ARRAY_SIZE(tps6105x_cells), NULL, 0, NULL);
+	return ret;
 }
 
 static int tps6105x_remove(struct i2c_client *client)
-- 
1.7.10.4