smatch: leds: potential null deref

smatch: leds: potential null deref

[Dan Carpenter]

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

Re: smatch: leds: potential null deref

[Dan Carpenter]

On Wed, Apr 07, 2010 at 12:18:50PM +0300, Dan Carpenter wrote:
> Hello,
> 
> Smatch complains about a potential null dereference but I don't know how
> to fix it.  Could you take a look?
> 

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

So don't hurry on my account.  :)

regards,
dan carpenter

RE: smatch: leds: potential null deref

[Haojian Zhuang]

[-- Attachment #1: Type: text/plain, Size: 1431 bytes --]

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:error27@gmail.com] 
Sent: 2010年4月7日 5:19 PM
To: Haojian Zhuang
Cc: Richard Purdie; kernel-janitors@vger.kernel.org
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

[-- Attachment #2: 0001-led-fix-parameter-checking.patch --]
[-- Type: application/octet-stream, Size: 1045 bytes --]

From 7b115e66a0ee22bdb50125bb834757e5eb29cda7 Mon Sep 17 00:00:00 2001
From: Haojian Zhuang <haojian.zhuang@marvell.com>
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.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
---
 drivers/leds/leds-88pm860x.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/leds-88pm860x.c b/drivers/leds/leds-88pm860x.c
index 16a60c0..46efc3a 100644
--- a/drivers/leds/leds-88pm860x.c
+++ b/drivers/leds/leds-88pm860x.c
@@ -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