From: Jack Pham <jackp@codeaurora.org>
To: Wenwen Wang <wenwen@cs.uga.edu>
Cc: Oliver Neukum <oneukum@suse.com>,
"David S. Miller" <davem@davemloft.net>,
"open list:USB \"USBNET\" DRIVER FRAMEWORK"
<netdev@vger.kernel.org>,
"open list:USB NETWORKING DRIVERS" <linux-usb@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] net: usbnet: fix a memory leak bug
Date: Wed, 14 Aug 2019 14:32:03 -0700 [thread overview]
Message-ID: <20190814213203.GA9754@jackp-linux.qualcomm.com> (raw)
In-Reply-To: <1565804493-7758-1-git-send-email-wenwen@cs.uga.edu>
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 <wenwen@cs.uga.edu>
> ---
> 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
next prev parent reply other threads:[~2019-08-14 21:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 17:41 [PATCH] net: usbnet: fix a memory leak bug Wenwen Wang
2019-08-14 21:32 ` Jack Pham [this message]
2019-08-15 10:42 ` Oliver Neukum
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