3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alan Stern <st...@rowland.harvard.edu>

commit 1633682053a7ee8058e10c76722b9b28e97fb73f upstream.

Using KASAN, Dmitry found a bug in the rh_call_control() routine: If
buffer allocation fails, the routine returns immediately without
unlinking its URB from the control endpoint, eventually leading to
linked-list corruption.

This patch fixes the problem by jumping to the end of the routine
(where the URB is unlinked) when an allocation failure occurs.

Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
Reported-and-tested-by: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/usb/core/hcd.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -498,8 +498,10 @@ static int rh_call_control (struct usb_h
         */
        tbuf_size =  max_t(u16, sizeof(struct usb_hub_descriptor), wLength);
        tbuf = kzalloc(tbuf_size, GFP_KERNEL);
-       if (!tbuf)
-               return -ENOMEM;
+       if (!tbuf) {
+               status = -ENOMEM;
+               goto err_alloc;
+       }
 
        bufp = tbuf;
 
@@ -702,6 +704,7 @@ error:
        }
 
        kfree(tbuf);
+ err_alloc:
 
        /* any errors get returned through the urb completion */
        spin_lock_irq(&hcd_root_hub_lock);


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