[PATCH v2] i2c: omap: Prevent NULL pointer dereference in remove

[PATCH v2] i2c: omap: Prevent NULL pointer dereference in remove

[Shubhrajyoti D]

Prevent the NULL pointer access by moving the platform_set_drvdata function
after the access of the pdev.

[  654.961761] Unable to handle kernel NULL pointer dereference at virtual address 00000070
[  654.970611] pgd = df254000
[  654.973480] [00000070] *pgd=9f1da831, *pte=00000000, *ppte=00000000
[  654.980163] Internal error: Oops: 17 [#1] SMP ARM
[  654.985076] Modules linked in:
[  654.988281] CPU: 1    Not tainted  (3.6.0-rc1-00031-ge547de1-dirty #339)
[  654.995330] PC is at omap_i2c_runtime_resume+0x8/0x148
[  655.000732] LR is at omap_i2c_runtime_resume+0x8/0x148

Signed-off-by: Shubhrajyoti D <shubhrajyoti-l0cyMroinI0@public.gmane.org>
---
v2: Implement Jean's suggestion of not deleting instead make it NULL at a safer time.

 drivers/i2c/busses/i2c-omap.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 5d19a49..c4ddb08 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1112,8 +1112,6 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
 	struct resource		*mem;
 	int ret;
 
-	platform_set_drvdata(pdev, NULL);
-
 	free_irq(dev->irq, dev);
 	i2c_del_adapter(&dev->adapter);
 	ret = pm_runtime_get_sync(&pdev->dev);
@@ -1127,6 +1125,7 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
 	kfree(dev);
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	release_mem_region(mem->start, resource_size(mem));
+	platform_set_drvdata(pdev, NULL);
 	return 0;
 }
 
-- 
1.7.5.4

Re: [PATCH v2] i2c: omap: Prevent NULL pointer dereference in remove

[Jean Delvare]

On Thu, 6 Sep 2012 17:31:56 +0530, Shubhrajyoti D wrote:
> Prevent the NULL pointer access by moving the platform_set_drvdata function
> after the access of the pdev.
> 
> [  654.961761] Unable to handle kernel NULL pointer dereference at virtual address 00000070
> [  654.970611] pgd = df254000
> [  654.973480] [00000070] *pgd=9f1da831, *pte=00000000, *ppte=00000000
> [  654.980163] Internal error: Oops: 17 [#1] SMP ARM
> [  654.985076] Modules linked in:
> [  654.988281] CPU: 1    Not tainted  (3.6.0-rc1-00031-ge547de1-dirty #339)
> [  654.995330] PC is at omap_i2c_runtime_resume+0x8/0x148
> [  655.000732] LR is at omap_i2c_runtime_resume+0x8/0x148
> 
> Signed-off-by: Shubhrajyoti D <shubhrajyoti-l0cyMroinI0@public.gmane.org>

Acked-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>

(This will rather go in Ben's or Wolfram's i2c tree.)

> ---
> v2: Implement Jean's suggestion of not deleting instead make it NULL at a safer time.
> 
>  drivers/i2c/busses/i2c-omap.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 5d19a49..c4ddb08 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -1112,8 +1112,6 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
>  	struct resource		*mem;
>  	int ret;
>  
> -	platform_set_drvdata(pdev, NULL);
> -
>  	free_irq(dev->irq, dev);
>  	i2c_del_adapter(&dev->adapter);
>  	ret = pm_runtime_get_sync(&pdev->dev);
> @@ -1127,6 +1125,7 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
>  	kfree(dev);
>  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	release_mem_region(mem->start, resource_size(mem));
> +	platform_set_drvdata(pdev, NULL);
>  	return 0;
>  }
>  


-- 
Jean Delvare

Re: [PATCH v2] i2c: omap: Prevent NULL pointer dereference in remove

[Shubhrajyoti Datta]

On Thu, Sep 6, 2012 at 5:51 PM, Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org> wrote:
> On Thu, 6 Sep 2012 17:31:56 +0530, Shubhrajyoti D wrote:
>> Prevent the NULL pointer access by moving the platform_set_drvdata function
>> after the access of the pdev.
>>
>> [  654.961761] Unable to handle kernel NULL pointer dereference at virtual address 00000070
>> [  654.970611] pgd = df254000
>> [  654.973480] [00000070] *pgd=9f1da831, *pte=00000000, *ppte=00000000
>> [  654.980163] Internal error: Oops: 17 [#1] SMP ARM
>> [  654.985076] Modules linked in:
>> [  654.988281] CPU: 1    Not tainted  (3.6.0-rc1-00031-ge547de1-dirty #339)
>> [  654.995330] PC is at omap_i2c_runtime_resume+0x8/0x148
>> [  655.000732] LR is at omap_i2c_runtime_resume+0x8/0x148
>>
>> Signed-off-by: Shubhrajyoti D <shubhrajyoti-l0cyMroinI0@public.gmane.org>
>
> Acked-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
>
> (This will rather go in Ben's or Wolfram's i2c tree.)

ping.

>
>> ---
>> v2: Implement Jean's suggestion of not deleting instead make it NULL at a safer time.
>>
>>  drivers/i2c/busses/i2c-omap.c |    3 +--
>>  1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
>> index 5d19a49..c4ddb08 100644
>> --- a/drivers/i2c/busses/i2c-omap.c
>> +++ b/drivers/i2c/busses/i2c-omap.c
>> @@ -1112,8 +1112,6 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
>>       struct resource         *mem;
>>       int ret;
>>
>> -     platform_set_drvdata(pdev, NULL);
>> -
>>       free_irq(dev->irq, dev);
>>       i2c_del_adapter(&dev->adapter);
>>       ret = pm_runtime_get_sync(&pdev->dev);
>> @@ -1127,6 +1125,7 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
>>       kfree(dev);
>>       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>       release_mem_region(mem->start, resource_size(mem));
>> +     platform_set_drvdata(pdev, NULL);
>>       return 0;
>>  }
>>
>
>
> --
> Jean Delvare
> --
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