Re: [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference

From: Wolfram Sang
Date: Sun Jun 01 2014 - 16:27:10 EST


On Sat, May 17, 2014 at 07:14:08PM +0200, Rickard Strandqvist wrote:
> There is otherwise a risk of a possible null pointer dereference.
>
> Was largely found by using a static code analysis program called cppcheck.

It is useful to put the output of the analyzer here.

>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-pxa.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index bbe6dfb..dbe5ebe 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -1269,7 +1269,9 @@ eremap:
> eclk:
> kfree(i2c);
> emalloc:
> - release_mem_region(res->start, resource_size(res));
> + if(res) {
> + release_mem_region(res->start, resource_size(res));
> + }

The proper fix is to move the release to the proper place, before kfree.
Even better would probably be a devm_* conversion.

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