[PATCH v2 1/2] usb: cdns3: fixed memory use after free at cdns3_gadget_ep_disable()

[Frank Li <Frank.Li@xxxxxxx>]

  ...
  cdns3_gadget_ep_free_request(&priv_ep->endpoint, &priv_req->request);
  list_del_init(&priv_req->list);
  ...

'priv_req' actually free at cdns3_gadget_ep_free_request(). But
list_del_init() use priv_req->list after it.

[ 1542.642868][  T534] BUG: KFENCE: use-after-free read in __list_del_entry_valid+0x10/0xd4
[ 1542.642868][  T534]
[ 1542.653162][  T534] Use-after-free read at 0x000000009ed0ba99 (in kfence-#3):
[ 1542.660311][  T534]  __list_del_entry_valid+0x10/0xd4
[ 1542.665375][  T534]  cdns3_gadget_ep_disable+0x1f8/0x388 [cdns3]
[ 1542.671571][  T534]  usb_ep_disable+0x44/0xe4
[ 1542.675948][  T534]  ffs_func_eps_disable+0x64/0xc8
[ 1542.680839][  T534]  ffs_func_set_alt+0x74/0x368
[ 1542.685478][  T534]  ffs_func_disable+0x18/0x28

Move list_del_init() before cdns3_gadget_ep_free_request() to resolve this
problem.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
Reviewed-by: Roger Quadros <rogerq@xxxxxxxxxx>
---
 drivers/usb/cdns3/cdns3-gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index aeca902ab6cc4..d6723d31fc6e2 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -2540,11 +2540,11 @@ static int cdns3_gadget_ep_disable(struct usb_ep *ep)
 
 	while (!list_empty(&priv_ep->wa2_descmiss_req_list)) {
 		priv_req = cdns3_next_priv_request(&priv_ep->wa2_descmiss_req_list);
+		list_del_init(&priv_req->list);
 
 		kfree(priv_req->request.buf);
 		cdns3_gadget_ep_free_request(&priv_ep->endpoint,
 					     &priv_req->request);
-		list_del_init(&priv_req->list);
 		--priv_ep->wa2_counter;
 	}
 
-- 
2.34.1