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Subject[PATCH 4/6] usb: gadget: mv_udc: check endpoint before queue dtd
Date
There is a corner case that endpoint is disabled by system shutdown
between check ep->desc and hold spin lock in mv_ep_queue. In this
case ep->ep.desc will be NULL and occur kernel panic when access
it in build_dtd.

Signed-off-by: Neil Zhang <zhangwm@marvell.com>
---
drivers/usb/gadget/mv_udc_core.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/usb/gadget/mv_udc_core.c b/drivers/usb/gadget/mv_udc_core.c
index d5a9bdf..a620cff 100644
--- a/drivers/usb/gadget/mv_udc_core.c
+++ b/drivers/usb/gadget/mv_udc_core.c
@@ -734,6 +734,14 @@ mv_ep_queue(struct usb_ep *_ep, struct usb_request *_req, gfp_t gfp_flags)

spin_lock_irqsave(&udc->lock, flags);

+ if (!ep->ep.desc) {
+ spin_unlock_irqrestore(&udc->lock, flags);
+ dev_info(&udc->dev->dev,
+ "%s is already disabled!\n", ep->name);
+ retval = -EINVAL;
+ goto err_unmap_dma;
+ }
+
/* build dtds and push them to device queue */
if (!req_to_dtd(req)) {
retval = queue_dtd(ep, req);
--
1.7.9.5


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