smatch: leds: potential null deref

Hello,

Smatch complains about a potential null dereference but I don't know how to fix it. Could you take a look?

drivers/leds/leds-88pm860x.c +269 pm860x_led_probe(28)
error: potential null derefence 'pdata'.
256 if (pdev->dev.parent->platform_data) {
257 pm860x_pdata = pdev->dev.parent->platform_data;
258 pdata = pm860x_pdata->led;
259 } else
260 pdata = NULL;
^^^^^^^^^^^^^

We set pdata to NULL here.

   261  
   262          data = kzalloc(sizeof(struct pm860x_led), GFP_KERNEL);
   263          if (data = NULL)
   264                  return -ENOMEM;
   265          strncpy(data->name, res->name, MFD_NAME_SIZE);
   266          dev_set_drvdata(&pdev->dev, data);
   267          data->chip = chip;
   268          data->i2c = (chip->id = CHIP_PM8606) ? chip->client : chip->companion;
   269          data->iset = pdata->iset;
                             ^^^^^^^^^^^^

We dereference it here.

regards,
dan carpenter

Sorry I should have mentioned that I'll be offline for probably a week.

So don't hurry on my account. :)

regards,
dan carpenter

Hi,

Excuse me on late response. Now I fix it.

Richard,
Could you help to review & merge this patch?

Thanks
Haojian

-----Original Message-----
From: Dan Carpenter [mailto:[email protected]]
Sent: 2010年4月7日 5:19 PM
To: Haojian Zhuang
Cc: Richard Purdie; [email protected]
Subject: smatch: leds: potential null deref

Hello,

Smatch complains about a potential null dereference but I don't know how to fix it. Could you take a look?

drivers/leds/leds-88pm860x.c +269 pm860x_led_probe(28)
error: potential null derefence 'pdata'.
256 if (pdev->dev.parent->platform_data) {
257 pm860x_pdata = pdev->dev.parent->platform_data;
258 pdata = pm860x_pdata->led;
259 } else
260 pdata = NULL;
^^^^^^^^^^^^^

We set pdata to NULL here.

   261  
   262          data = kzalloc(sizeof(struct pm860x_led), GFP_KERNEL);
   263          if (data == NULL)
   264                  return -ENOMEM;
   265          strncpy(data->name, res->name, MFD_NAME_SIZE);
   266          dev_set_drvdata(&pdev->dev, data);
   267          data->chip = chip;
   268          data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion;
   269          data->iset = pdata->iset;
                             ^^^^^^^^^^^^

We dereference it here.

regards,
dan carpenter

From 7b115e66a0ee22bdb50125bb834757e5eb29cda7 Mon Sep 17 00:00:00 2001
From: Haojian Zhuang <[email protected]>
Date: Fri, 9 Apr 2010 12:57:27 -0400
Subject: [PATCH] led: fix parameter checking

If platform data isn't assigned, no error detection on this. Now check it and exit if it's not assigned.

---
 drivers/leds/leds-88pm860x.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

index 16a60c0..46efc3a 100644
@@ -256,8 +256,10 @@ static int pm860x_led_probe(struct platform_device *pdev)
 	if (pdev->dev.parent->platform_data) {
 		pm860x_pdata = pdev->dev.parent->platform_data;
 		pdata = pm860x_pdata->led;
-	} else
-		pdata = NULL;
+	} else {
+		dev_err(&pdev->dev, "missing platform data\n");
+		return -EINVAL;
+	}
 
 	data = kzalloc(sizeof(struct pm860x_led), GFP_KERNEL);
 	if (data == NULL)

1.5.6.5