2013-04-23 02:44:37

by Wei Yongjun

Subject: [PATCH -next] mei: fix krealloc() misuse in in mei_cl_irq_read_msg()

From: Wei Yongjun <[email protected]>

If krealloc() returns NULL, it doesn't free the original. So any code
of the form 'foo = krealloc(foo, ...);' is almost certainly a bug.

Introduced by commit fcb136e1ac5774909e0d85189f721b8dfa800e0f(mei: fix
reading large reposnes)

Signed-off-by: Wei Yongjun <[email protected]>
---
drivers/misc/mei/interrupt.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 37a8c35..089c516 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -148,16 +148,16 @@ static int mei_cl_irq_read_msg(struct mei_device *dev,
dev_dbg(&dev->pdev->dev, "message overflow. size %d len %d idx %ld\n",
cb->response_buffer.size,
mei_hdr->length, cb->buf_idx);
- cb->response_buffer.data =
- krealloc(cb->response_buffer.data,
- mei_hdr->length + cb->buf_idx,
- GFP_KERNEL);
+ buffer = krealloc(cb->response_buffer.data,
+ mei_hdr->length + cb->buf_idx,
+ GFP_KERNEL);

- if (!cb->response_buffer.data) {
+ if (!buffer) {
dev_err(&dev->pdev->dev, "allocation failed.\n");
list_del(&cb->list);
return -ENOMEM;
}
+ cb->response_buffer.data = buffer;
cb->response_buffer.size =
mei_hdr->length + cb->buf_idx;
}

2013-04-23 04:29:15

by Tomas Winkler

Subject: RE: [PATCH -next] mei: fix krealloc() misuse in in mei_cl_irq_read_msg()

> From: Wei Yongjun <[email protected]>
>
> If krealloc() returns NULL, it doesn't free the original. So any code of the form
> 'foo = krealloc(foo, ...);' is almost certainly a bug.
>
> Introduced by commit fcb136e1ac5774909e0d85189f721b8dfa800e0f(mei: fix
> reading large reposnes)
>
> Signed-off-by: Wei Yongjun <[email protected]>
Thanks, strange that my checkpatch didn't shout on that.
I don't like the unrelated reuse of the buffer variable but the code looks correct so ACK.

Thanks
Tomas

> ---
> drivers/misc/mei/interrupt.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c index
> 37a8c35..089c516 100644
> --- a/drivers/misc/mei/interrupt.c
> +++ b/drivers/misc/mei/interrupt.c
> @@ -148,16 +148,16 @@ static int mei_cl_irq_read_msg(struct mei_device
> *dev,
> dev_dbg(&dev->pdev->dev, "message overflow.
> size %d len %d idx %ld\n",
> cb->response_buffer.size,
> mei_hdr->length, cb->buf_idx);
> - cb->response_buffer.data =
> - krealloc(cb->response_buffer.data,
> - mei_hdr->length + cb->buf_idx,
> - GFP_KERNEL);
> + buffer = krealloc(cb->response_buffer.data,
> + mei_hdr->length + cb->buf_idx,
> + GFP_KERNEL);
>
> - if (!cb->response_buffer.data) {
> + if (!buffer) {
> dev_err(&dev->pdev->dev, "allocation
> failed.\n");
> list_del(&cb->list);
> return -ENOMEM;
> }
> + cb->response_buffer.data = buffer;
> cb->response_buffer.size =
> mei_hdr->length + cb->buf_idx;
> }