The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e752dbc59e1241b13b8c4f7b6eb582862e7668fe Mon Sep 17 00:00:00 2001
From: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Date: Mon, 24 May 2021 15:01:55 +0900 Subject: [PATCH] usb: gadget: udc: renesas_usb3: Fix a race in usb3_start_pipen()
The usb3_start_pipen() is called by renesas_usb3_ep_queue() and usb3_request_done_pipen() so that usb3_start_pipen() is possible to cause a race when getting usb3_first_req like below:
renesas_usb3_ep_queue() spin_lock_irqsave() list_add_tail() spin_unlock_irqrestore() usb3_start_pipen() usb3_first_req = usb3_get_request() --- [1] --- interrupt --- usb3_irq_dma_int() usb3_request_done_pipen() usb3_get_request() usb3_start_pipen() usb3_first_req = usb3_get_request() ... (the req is possible to be finished in the interrupt)
The usb3_first_req [1] above may have been finished after the interrupt ended so that this driver caused to start a transfer wrongly. To fix this issue, getting/checking the usb3_first_req are under spin_lock_irqsave() in the same section.
Fixes: 746bfe63bba3 ("usb: gadget: renesas_usb3: add support for Renesas USB3.0 peripheral controller") Cc: stable stable@vger.kernel.org Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Link: https://lore.kernel.org/r/20210524060155.1178724-1-yoshihiro.shimoda.uh@rene... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c index 0c418ce50ba0..f1b35a39d1ba 100644 --- a/drivers/usb/gadget/udc/renesas_usb3.c +++ b/drivers/usb/gadget/udc/renesas_usb3.c @@ -1488,7 +1488,7 @@ static void usb3_start_pipen(struct renesas_usb3_ep *usb3_ep, struct renesas_usb3_request *usb3_req) { struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep); - struct renesas_usb3_request *usb3_req_first = usb3_get_request(usb3_ep); + struct renesas_usb3_request *usb3_req_first; unsigned long flags; int ret = -EAGAIN; u32 enable_bits = 0; @@ -1496,7 +1496,8 @@ static void usb3_start_pipen(struct renesas_usb3_ep *usb3_ep, spin_lock_irqsave(&usb3->lock, flags); if (usb3_ep->halt || usb3_ep->started) goto out; - if (usb3_req != usb3_req_first) + usb3_req_first = __usb3_get_request(usb3_ep); + if (!usb3_req_first || usb3_req != usb3_req_first) goto out;
if (usb3_pn_change(usb3, usb3_ep->num) < 0)