patch "usb: gadget: ether: Fix race between gether_disconnect and rx_submit" added to usb-next

This is a note to let you know that I've just added the patch titled

usb: gadget: ether: Fix race between gether_disconnect and rx_submit

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release during the merge window.

If you have any questions about this process, please let me know.

From d29fcf7078bc8be2b6366cbd4418265b53c94fac Mon Sep 17 00:00:00 2001
From: Kiruthika Varadarajan <[email protected]>
Date: Tue, 18 Jun 2019 08:39:06 +0000
Subject: usb: gadget: ether: Fix race between gether_disconnect and rx_submit

On spin lock release in rx_submit, gether_disconnect get a chance to run, it makes port_usb NULL, rx_submit access NULL port USB, hence null pointer crash.

Fixed by releasing the lock in rx_submit after port_usb is used.

---
 drivers/usb/gadget/function/u_ether.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

index 737bd77a575d..2929bb47a618 100644
@@ -186,11 +186,12 @@ rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
 		out = dev->port_usb->out_ep;
 	else
 		out = NULL;
-	spin_unlock_irqrestore(&dev->lock, flags);
 
 	if (!out)
+	{
+		spin_unlock_irqrestore(&dev->lock, flags);
 		return -ENOTCONN;
-
+	}
 
 	/* Padding up to RX_EXTRA handles minor disagreements with host.
 	 * Normally we use the USB "terminate on short read" convention;

@@ -214,6 +215,7 @@ rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
 
 	if (dev->port_usb->is_fixed)
 		size = max_t(size_t, size, dev->port_usb->fixed_out_len);
+	spin_unlock_irqrestore(&dev->lock, flags);
 
 	skb = __netdev_alloc_skb(dev->net, size + NET_IP_ALIGN, gfp_flags);
 	if (skb == NULL) {

2.22.0