In usbnet_start_xmit(), 'urb->sg' is allocated through kmalloc_array() by
invoking build_dma_sg(). Later on, if 'CONFIG_PM' is defined and the if
branch is taken, the execution will go to the label 'deferred'. However,
'urb->sg' is not deallocated on this execution path, leading to a memory
leak bug.
Signed-off-by: Wenwen Wang <[email protected]>
---
drivers/net/usb/usbnet.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 72514c4..f17fafa 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1433,6 +1433,7 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
usb_anchor_urb(urb, &dev->deferred);
/* no use to process more packets */
netif_stop_queue(net);
+ kfree(urb->sg);
usb_put_urb(urb);
spin_unlock_irqrestore(&dev->txq.lock, flags);
netdev_dbg(dev->net, "Delaying transmission for resumption\n");
--
2.7.4
On Wed, Aug 14, 2019 at 12:41:33PM -0500, Wenwen Wang wrote:
> In usbnet_start_xmit(), 'urb->sg' is allocated through kmalloc_array() by
> invoking build_dma_sg(). Later on, if 'CONFIG_PM' is defined and the if
> branch is taken, the execution will go to the label 'deferred'. However,
> 'urb->sg' is not deallocated on this execution path, leading to a memory
> leak bug.
>
> Signed-off-by: Wenwen Wang <[email protected]>
> ---
> drivers/net/usb/usbnet.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
> index 72514c4..f17fafa 100644
> --- a/drivers/net/usb/usbnet.c
> +++ b/drivers/net/usb/usbnet.c
> @@ -1433,6 +1433,7 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
> usb_anchor_urb(urb, &dev->deferred);
> /* no use to process more packets */
> netif_stop_queue(net);
> + kfree(urb->sg);
> usb_put_urb(urb);
The URB itself is not getting freed here; it is merely added to the
anchor list and will be submitted later upon usbnet_resume(). Therefore
freeing the SG list is premature and incorrect, as it will get freed in
either the tx_complete/tx_done path or upon URB submission failure.
> spin_unlock_irqrestore(&dev->txq.lock, flags);
> netdev_dbg(dev->net, "Delaying transmission for resumption\n");
Jack
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
Am Mittwoch, den 14.08.2019, 12:41 -0500 schrieb Wenwen Wang:
> In usbnet_start_xmit(), 'urb->sg' is allocated through kmalloc_array() by
> invoking build_dma_sg(). Later on, if 'CONFIG_PM' is defined and the if
> branch is taken, the execution will go to the label 'deferred'. However,
> 'urb->sg' is not deallocated on this execution path, leading to a memory
> leak bug.
Just to make this clear:
> Signed-off-by: Wenwen Wang <[email protected]>
NACK
For the reason Jack explained. Deferral is not a failure.
Regards
Oliver