RE: [PATCH] vdpa: Fix memory leak in error unwinding path

From: Stefano Garzarella <sgarzare@redhat.com>
Sent: Monday, February 15, 2021 5:16 PM

On Sat, Feb 13, 2021 at 08:39:19PM +0200, Parav Pandit wrote:

quoted

When device get command fails to find the device or mdev, it skips to
free the skb during error unwinding path.
Fix it by freeing in error unwind path.

Fixes: a12a2f694ce8 ("vdpa: Enable user to query vdpa device info")
Signed-off-by: Parav Pandit <redacted>
---
drivers/vdpa/vdpa.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index

3d997b389345..e3f1bfdf8d6f 100644

--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c

@@ -540,20 +540,22 @@ static int vdpa_nl_cmd_dev_get_doit(struct

sk_buff *skb, struct genl_info *info)

quoted

	if (!dev) {
		mutex_unlock(&vdpa_dev_mutex);
		NL_SET_ERR_MSG_MOD(info->extack, "device not found");
-		return -ENODEV;
+		err = -ENODEV;
+		goto err;
	}
	vdev = container_of(dev, struct vdpa_device, dev);
	if (!vdev->mdev) {
		mutex_unlock(&vdpa_dev_mutex);
		put_device(dev);
-		return -EINVAL;
+		err = -EINVAL;
+		goto err;
	}
	err = vdpa_dev_fill(vdev, msg, info->snd_portid, info->snd_seq, 0,

info->extack);

quoted

	if (!err)
		err = genlmsg_reply(msg, info);
	put_device(dev);
	mutex_unlock(&vdpa_dev_mutex);
-
+err:

If we put this label before mutex_unlock(), we can remove that call in the
error paths.

Maybe we can also add another label before put_device() and jump to it in
the "if (!vdev->mdev)" case.

Yep, I will send v2.
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