[PATCH 3/8] drivers/media/video/hdpvr: introduce missing kfree

[PATCH 3/8] drivers/media/video/hdpvr: introduce missing kfree

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

Error handling code following a kzalloc should free the allocated data.

The semantic match that finds the problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,f1,l;
position p1,p2;
expression *ptr != NULL;
@@

x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...x...+> }
(
x->f1 = E
|
 (x->f1 == NULL || ...)
|
 f(...,x->f1,...)
)
...>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
---
 drivers/media/video/hdpvr/hdpvr-video.c        |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/media/video/hdpvr/hdpvr-video.c b/drivers/media/video/hdpvr/hdpvr-video.c
index 2eb9dc2..0d17ce5 100644
--- a/drivers/media/video/hdpvr/hdpvr-video.c
+++ b/drivers/media/video/hdpvr/hdpvr-video.c
@@ -132,7 +132,7 @@ int hdpvr_alloc_buffers(struct hdpvr_device *dev, uint count)
 		buf = kzalloc(sizeof(struct hdpvr_buffer), GFP_KERNEL);
 		if (!buf) {
 			v4l2_err(&dev->v4l2_dev, "cannot allocate buffer\n");
-			goto exit;
+			goto exit_nobuf;
 		}
 		buf->dev = dev;
 
@@ -162,6 +162,8 @@ int hdpvr_alloc_buffers(struct hdpvr_device *dev, uint count)
 	}
 	return 0;
 exit:
+	kfree(buf);
+exit_nobuf:
 	hdpvr_free_buffers(dev);
 	return retval;
 }

Re: [PATCH 3/8] drivers/media/video/hdpvr: introduce missing kfree

[Janne Grunau]

On Fri, Sep 11, 2009 at 06:21:35PM +0200, Julia Lawall wrote:
> 
> Error handling code following a kzalloc should free the allocated data.

Thanks for the report. I'll commit a different patch which adds the buffer
to the buffer list as soon it is allocated. The hdpvr_free_buffers() in the
error handling code will clean it up then. See below:

diff --git a/linux/drivers/media/video/hdpvr/hdpvr-video.c b/linux/drivers/media/video/hdpvr/hdpvr-video.c
--- a/linux/drivers/media/video/hdpvr/hdpvr-video.c
+++ b/linux/drivers/media/video/hdpvr/hdpvr-video.c
@@ -134,6 +134,8 @@
                        v4l2_err(&dev->v4l2_dev, "cannot allocate buffer\n");
                        goto exit;
                }
+               list_add_tail(&buf->buff_list, &dev->free_buff_list);
+
                buf->dev = dev;

                urb = usb_alloc_urb(0, GFP_KERNEL);
@@ -158,7 +160,6 @@
                                  hdpvr_read_bulk_callback, buf);

                buf->status = BUFSTAT_AVAILABLE;
-               list_add_tail(&buf->buff_list, &dev->free_buff_list);
        }
        return 0;
 exit:

Re: [PATCH 3/8] drivers/media/video/hdpvr: introduce missing kfree

[Mauro Carvalho Chehab]

Hi Janne,

Janne Grunau wrote:
> On Fri, Sep 11, 2009 at 06:21:35PM +0200, Julia Lawall wrote:
>> Error handling code following a kzalloc should free the allocated data.
> 
> Thanks for the report. I'll commit a different patch which adds the buffer
> to the buffer list as soon it is allocated. The hdpvr_free_buffers() in the
> error handling code will clean it up then. See below:

Any news about this subject? The current upstream code still misses the change bellow

> 
> diff --git a/linux/drivers/media/video/hdpvr/hdpvr-video.c b/linux/drivers/media/video/hdpvr/hdpvr-video.c
> --- a/linux/drivers/media/video/hdpvr/hdpvr-video.c
> +++ b/linux/drivers/media/video/hdpvr/hdpvr-video.c
> @@ -134,6 +134,8 @@
>                         v4l2_err(&dev->v4l2_dev, "cannot allocate buffer\n");
>                         goto exit;
>                 }
> +               list_add_tail(&buf->buff_list, &dev->free_buff_list);
> +
>                 buf->dev = dev;
> 
>                 urb = usb_alloc_urb(0, GFP_KERNEL);
> @@ -158,7 +160,6 @@
>                                   hdpvr_read_bulk_callback, buf);
> 
>                 buf->status = BUFSTAT_AVAILABLE;
> -               list_add_tail(&buf->buff_list, &dev->free_buff_list);
>         }
>         return 0;
>  exit:
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
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> More majordomo info at  http://vger.kernel.org/majordomo-info.html


-- 

Cheers,
Mauro

Re: [PATCH 3/8] drivers/media/video/hdpvr: introduce missing kfree

[Janne Grunau]

Hej, 

On Tue, Feb 02, 2010 at 01:19:15PM -0200, Mauro Carvalho Chehab wrote:
> 
> Janne Grunau wrote:
> > On Fri, Sep 11, 2009 at 06:21:35PM +0200, Julia Lawall wrote:
> >> Error handling code following a kzalloc should free the allocated data.
> > 
> > Thanks for the report. I'll commit a different patch which adds the buffer
> > to the buffer list as soon it is allocated. The hdpvr_free_buffers() in the
> > error handling code will clean it up then. See below:
> 
> Any news about this subject? The current upstream code still misses the change bellow

it was fixed differently in cd0e280f

kind regards,
Janne

Re: [PATCH 3/8] drivers/media/video/hdpvr: introduce missing kfree

[Mauro Carvalho Chehab]

Janne Grunau wrote:
> Hej, 
> 
> On Tue, Feb 02, 2010 at 01:19:15PM -0200, Mauro Carvalho Chehab wrote:
>> Janne Grunau wrote:
>>> On Fri, Sep 11, 2009 at 06:21:35PM +0200, Julia Lawall wrote:
>>>> Error handling code following a kzalloc should free the allocated data.
>>> Thanks for the report. I'll commit a different patch which adds the buffer
>>> to the buffer list as soon it is allocated. The hdpvr_free_buffers() in the
>>> error handling code will clean it up then. See below:
>> Any news about this subject? The current upstream code still misses the change bellow
> 
> it was fixed differently in cd0e280f

Thanks! I'm removing it from my queue :)

Now, the only hdpvr patch is this one:

hdpvr-video: cleanup signedness                                         http://patchwork.kernel.org/patch/74902


Cheers,
Mauro