Re: [PATCH 1/2] usb: chipidea: udc: improve error handling on ep_queue

From: Peter Chen
Date: Mon Sep 21 2015 - 03:42:31 EST


On Fri, Sep 18, 2015 at 06:12:40PM +0100, eu@xxxxxxxxxxxxxxxxx wrote:
> From: "Felipe F. Tonello" <eu@xxxxxxxxxxxxxxxxx>
>
> _ep_queue() didn't check for errors when using add_td_to_list()
> which can fail if dma_pool_alloc fails, thus causing a kernel

Would you find the root cause why dma_pool_alloc fails?

> panic when lastnode->ptr is NULL.
>
> Signed-off-by: Felipe F. Tonello <eu@xxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/chipidea/udc.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 764f668..7169113e 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -404,9 +404,9 @@ static inline u8 _usb_addr(struct ci_hw_ep *ep)
> }
>
> /**
> - * _hardware_queue: configures a request at hardware level
> - * @gadget: gadget
> + * _hardware_enqueue: configures a request at hardware level
> * @hwep: endpoint
> + * @hwreq: request
> *
> * This function returns an error code
> */
> @@ -435,19 +435,27 @@ static int _hardware_enqueue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
> if (hwreq->req.dma % PAGE_SIZE)
> pages--;
>
> - if (rest == 0)
> - add_td_to_list(hwep, hwreq, 0);
> + if (rest == 0) {
> + ret = add_td_to_list(hwep, hwreq, 0);
> + if (ret < 0)
> + goto done;
> + }
>
> while (rest > 0) {
> unsigned count = min(hwreq->req.length - hwreq->req.actual,
> (unsigned)(pages * CI_HDRC_PAGE_SIZE));
> - add_td_to_list(hwep, hwreq, count);
> + ret = add_td_to_list(hwep, hwreq, count);
> + if (ret < 0)
> + goto done;
> rest -= count;
> }
>
> if (hwreq->req.zero && hwreq->req.length
> - && (hwreq->req.length % hwep->ep.maxpacket == 0))
> - add_td_to_list(hwep, hwreq, 0);
> + && (hwreq->req.length % hwep->ep.maxpacket == 0)) {
> + ret = add_td_to_list(hwep, hwreq, 0);
> + if (ret < 0)
> + goto done;
> + }
>
> firstnode = list_first_entry(&hwreq->tds, struct td_node, td);
>
> @@ -750,8 +758,12 @@ static void isr_get_status_complete(struct usb_ep *ep, struct usb_request *req)
>
> /**
> * _ep_queue: queues (submits) an I/O request to an endpoint
> + * @ep: endpoint
> + * @req: request
> + * @gfp_flags: GFP flags (not used)
> *
> * Caller must hold lock
> + * This function returns an error code
> */
> static int _ep_queue(struct usb_ep *ep, struct usb_request *req,
> gfp_t __maybe_unused gfp_flags)
> --
> 2.1.4
>

--

Best Regards,
Peter Chen
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/