USB: pxa27x_udc: Fix deadlocks on request queueing
As reported by Antonio, there are cases where the ep->lock can be taken twice, triggering a deadlock. The typical sequence is : irq_handler \ -> gadget.complete() \ -> pxa27x_udc.pxa_ep_queue() : ep->lock is taken \ -> gadget.complete() \ -> pxa27x_udc.pxa_ep_queue() : ep->lock is taken ==> *deadlock* The patch fixes this by : - releasing the lock each time gadget.complete() is called - adding a check in handle_ep() to detect a recursive call, in which case the function becomes on no-op. The patch is still not good enough for ep0. For this unique endpoint, another well thought over patch will be needed. Reported-by: Antonio Ospite <ospite@studenti.unina.it> Tested-by: Antonio Ospite <ospite@studenti.unina.it> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Eric Miao <eric.y.miao@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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5e23e90f33
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@ -742,13 +742,17 @@ static void ep_del_request(struct pxa_ep *ep, struct pxa27x_request *req)
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* @ep: pxa physical endpoint
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* @req: pxa request
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* @status: usb request status sent to gadget API
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* @pflags: flags of previous spinlock_irq_save() or NULL if no lock held
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*
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* Context: ep->lock held
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* Context: ep->lock held if flags not NULL, else ep->lock released
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*
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* Retire a pxa27x usb request. Endpoint must be locked.
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*/
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static void req_done(struct pxa_ep *ep, struct pxa27x_request *req, int status)
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static void req_done(struct pxa_ep *ep, struct pxa27x_request *req, int status,
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unsigned long *pflags)
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{
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unsigned long flags;
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ep_del_request(ep, req);
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if (likely(req->req.status == -EINPROGRESS))
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req->req.status = status;
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@ -760,38 +764,48 @@ static void req_done(struct pxa_ep *ep, struct pxa27x_request *req, int status)
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&req->req, status,
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req->req.actual, req->req.length);
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if (pflags)
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spin_unlock_irqrestore(&ep->lock, *pflags);
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local_irq_save(flags);
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req->req.complete(&req->udc_usb_ep->usb_ep, &req->req);
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local_irq_restore(flags);
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if (pflags)
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spin_lock_irqsave(&ep->lock, *pflags);
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}
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/**
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* ep_end_out_req - Ends endpoint OUT request
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* @ep: physical endpoint
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* @req: pxa request
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* @pflags: flags of previous spinlock_irq_save() or NULL if no lock held
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*
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* Context: ep->lock held
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* Context: ep->lock held or released (see req_done())
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*
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* Ends endpoint OUT request (completes usb request).
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*/
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static void ep_end_out_req(struct pxa_ep *ep, struct pxa27x_request *req)
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static void ep_end_out_req(struct pxa_ep *ep, struct pxa27x_request *req,
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unsigned long *pflags)
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{
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inc_ep_stats_reqs(ep, !USB_DIR_IN);
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req_done(ep, req, 0);
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req_done(ep, req, 0, pflags);
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}
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/**
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* ep0_end_out_req - Ends control endpoint OUT request (ends data stage)
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* @ep: physical endpoint
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* @req: pxa request
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* @pflags: flags of previous spinlock_irq_save() or NULL if no lock held
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*
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* Context: ep->lock held
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* Context: ep->lock held or released (see req_done())
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*
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* Ends control endpoint OUT request (completes usb request), and puts
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* control endpoint into idle state
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*/
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static void ep0_end_out_req(struct pxa_ep *ep, struct pxa27x_request *req)
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static void ep0_end_out_req(struct pxa_ep *ep, struct pxa27x_request *req,
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unsigned long *pflags)
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{
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set_ep0state(ep->dev, OUT_STATUS_STAGE);
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ep_end_out_req(ep, req);
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ep_end_out_req(ep, req, pflags);
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ep0_idle(ep->dev);
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}
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@ -799,31 +813,35 @@ static void ep0_end_out_req(struct pxa_ep *ep, struct pxa27x_request *req)
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* ep_end_in_req - Ends endpoint IN request
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* @ep: physical endpoint
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* @req: pxa request
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* @pflags: flags of previous spinlock_irq_save() or NULL if no lock held
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*
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* Context: ep->lock held
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* Context: ep->lock held or released (see req_done())
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*
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* Ends endpoint IN request (completes usb request).
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*/
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static void ep_end_in_req(struct pxa_ep *ep, struct pxa27x_request *req)
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static void ep_end_in_req(struct pxa_ep *ep, struct pxa27x_request *req,
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unsigned long *pflags)
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{
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inc_ep_stats_reqs(ep, USB_DIR_IN);
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req_done(ep, req, 0);
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req_done(ep, req, 0, pflags);
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}
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/**
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* ep0_end_in_req - Ends control endpoint IN request (ends data stage)
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* @ep: physical endpoint
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* @req: pxa request
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* @pflags: flags of previous spinlock_irq_save() or NULL if no lock held
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*
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* Context: ep->lock held
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* Context: ep->lock held or released (see req_done())
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*
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* Ends control endpoint IN request (completes usb request), and puts
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* control endpoint into status state
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*/
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static void ep0_end_in_req(struct pxa_ep *ep, struct pxa27x_request *req)
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static void ep0_end_in_req(struct pxa_ep *ep, struct pxa27x_request *req,
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unsigned long *pflags)
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{
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set_ep0state(ep->dev, IN_STATUS_STAGE);
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ep_end_in_req(ep, req);
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ep_end_in_req(ep, req, pflags);
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}
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/**
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@ -831,19 +849,22 @@ static void ep0_end_in_req(struct pxa_ep *ep, struct pxa27x_request *req)
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* @ep: pxa endpoint
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* @status: usb request status
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*
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* Context: ep->lock held
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* Context: ep->lock released
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*
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* Dequeues all requests on an endpoint. As a side effect, interrupts will be
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* disabled on that endpoint (because no more requests).
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*/
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static void nuke(struct pxa_ep *ep, int status)
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{
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struct pxa27x_request *req;
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struct pxa27x_request *req;
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unsigned long flags;
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spin_lock_irqsave(&ep->lock, flags);
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while (!list_empty(&ep->queue)) {
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req = list_entry(ep->queue.next, struct pxa27x_request, queue);
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req_done(ep, req, status);
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req_done(ep, req, status, &flags);
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}
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spin_unlock_irqrestore(&ep->lock, flags);
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}
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/**
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@ -1123,6 +1144,7 @@ static int pxa_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
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int rc = 0;
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int is_first_req;
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unsigned length;
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int recursion_detected;
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req = container_of(_req, struct pxa27x_request, req);
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udc_usb_ep = container_of(_ep, struct udc_usb_ep, usb_ep);
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@ -1152,6 +1174,7 @@ static int pxa_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
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return -EMSGSIZE;
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spin_lock_irqsave(&ep->lock, flags);
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recursion_detected = ep->in_handle_ep;
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is_first_req = list_empty(&ep->queue);
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ep_dbg(ep, "queue req %p(first=%s), len %d buf %p\n",
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@ -1161,12 +1184,12 @@ static int pxa_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
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if (!ep->enabled) {
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_req->status = -ESHUTDOWN;
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rc = -ESHUTDOWN;
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goto out;
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goto out_locked;
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}
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if (req->in_use) {
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ep_err(ep, "refusing to queue req %p (already queued)\n", req);
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goto out;
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goto out_locked;
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}
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length = _req->length;
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@ -1174,12 +1197,13 @@ static int pxa_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
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_req->actual = 0;
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ep_add_request(ep, req);
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spin_unlock_irqrestore(&ep->lock, flags);
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if (is_ep0(ep)) {
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switch (dev->ep0state) {
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case WAIT_ACK_SET_CONF_INTERF:
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if (length == 0) {
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ep_end_in_req(ep, req);
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ep_end_in_req(ep, req, NULL);
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} else {
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ep_err(ep, "got a request of %d bytes while"
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"in state WAIT_ACK_SET_CONF_INTERF\n",
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@ -1192,12 +1216,12 @@ static int pxa_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
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case IN_DATA_STAGE:
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if (!ep_is_full(ep))
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if (write_ep0_fifo(ep, req))
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ep0_end_in_req(ep, req);
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ep0_end_in_req(ep, req, NULL);
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break;
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case OUT_DATA_STAGE:
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if ((length == 0) || !epout_has_pkt(ep))
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if (read_ep0_fifo(ep, req))
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ep0_end_out_req(ep, req);
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ep0_end_out_req(ep, req, NULL);
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break;
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default:
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ep_err(ep, "odd state %s to send me a request\n",
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@ -1207,12 +1231,15 @@ static int pxa_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
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break;
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}
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} else {
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handle_ep(ep);
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if (!recursion_detected)
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handle_ep(ep);
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}
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out:
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spin_unlock_irqrestore(&ep->lock, flags);
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return rc;
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out_locked:
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spin_unlock_irqrestore(&ep->lock, flags);
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goto out;
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}
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/**
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@ -1242,13 +1269,14 @@ static int pxa_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
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/* make sure it's actually queued on this endpoint */
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list_for_each_entry(req, &ep->queue, queue) {
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if (&req->req == _req) {
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req_done(ep, req, -ECONNRESET);
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rc = 0;
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break;
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}
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}
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spin_unlock_irqrestore(&ep->lock, flags);
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if (!rc)
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req_done(ep, req, -ECONNRESET, NULL);
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return rc;
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}
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@ -1445,7 +1473,6 @@ static int pxa_ep_disable(struct usb_ep *_ep)
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{
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struct pxa_ep *ep;
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struct udc_usb_ep *udc_usb_ep;
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unsigned long flags;
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if (!_ep)
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return -EINVAL;
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@ -1455,10 +1482,8 @@ static int pxa_ep_disable(struct usb_ep *_ep)
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if (!ep || is_ep0(ep) || !list_empty(&ep->queue))
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return -EINVAL;
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spin_lock_irqsave(&ep->lock, flags);
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ep->enabled = 0;
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nuke(ep, -ESHUTDOWN);
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spin_unlock_irqrestore(&ep->lock, flags);
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pxa_ep_fifo_flush(_ep);
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udc_usb_ep->pxa_ep = NULL;
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@ -1907,8 +1932,10 @@ static void handle_ep0_ctrl_req(struct pxa_udc *udc,
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} u;
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int i;
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int have_extrabytes = 0;
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unsigned long flags;
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nuke(ep, -EPROTO);
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spin_lock_irqsave(&ep->lock, flags);
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/*
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* In the PXA320 manual, in the section about Back-to-Back setup
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@ -1947,10 +1974,13 @@ static void handle_ep0_ctrl_req(struct pxa_udc *udc,
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/* Tell UDC to enter Data Stage */
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ep_write_UDCCSR(ep, UDCCSR0_SA | UDCCSR0_OPC);
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spin_unlock_irqrestore(&ep->lock, flags);
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i = udc->driver->setup(&udc->gadget, &u.r);
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spin_lock_irqsave(&ep->lock, flags);
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if (i < 0)
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goto stall;
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out:
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spin_unlock_irqrestore(&ep->lock, flags);
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return;
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stall:
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ep_dbg(ep, "protocol STALL, udccsr0=%03x err %d\n",
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if (req && !ep_is_full(ep))
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completed = write_ep0_fifo(ep, req);
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if (completed)
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ep0_end_in_req(ep, req);
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ep0_end_in_req(ep, req, NULL);
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break;
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case OUT_DATA_STAGE: /* SET_DESCRIPTOR */
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if (epout_has_pkt(ep) && req)
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completed = read_ep0_fifo(ep, req);
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if (completed)
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ep0_end_out_req(ep, req);
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ep0_end_out_req(ep, req, NULL);
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break;
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case STALL:
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ep_write_UDCCSR(ep, UDCCSR0_FST);
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@ -2091,7 +2121,7 @@ static void handle_ep0(struct pxa_udc *udc, int fifo_irq, int opc_irq)
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* Tries to transfer all pending request data into the endpoint and/or
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* transfer all pending data in the endpoint into usb requests.
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*
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* Is always called when in_interrupt() or with ep->lock held.
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* Is always called when in_interrupt() and with ep->lock released.
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*/
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static void handle_ep(struct pxa_ep *ep)
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{
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@ -2100,10 +2130,17 @@ static void handle_ep(struct pxa_ep *ep)
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u32 udccsr;
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int is_in = ep->dir_in;
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int loop = 0;
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unsigned long flags;
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spin_lock_irqsave(&ep->lock, flags);
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if (ep->in_handle_ep)
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goto recursion_detected;
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ep->in_handle_ep = 1;
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do {
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completed = 0;
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udccsr = udc_ep_readl(ep, UDCCSR);
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if (likely(!list_empty(&ep->queue)))
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req = list_entry(ep->queue.next,
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struct pxa27x_request, queue);
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if (unlikely(is_in)) {
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if (likely(!ep_is_full(ep)))
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completed = write_fifo(ep, req);
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if (completed)
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ep_end_in_req(ep, req);
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} else {
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if (likely(epout_has_pkt(ep)))
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completed = read_fifo(ep, req);
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if (completed)
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ep_end_out_req(ep, req);
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}
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if (completed) {
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if (is_in)
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ep_end_in_req(ep, req, &flags);
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else
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ep_end_out_req(ep, req, &flags);
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}
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} while (completed);
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ep->in_handle_ep = 0;
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recursion_detected:
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spin_unlock_irqrestore(&ep->lock, flags);
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}
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/**
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@ -318,6 +318,11 @@ struct udc_usb_ep {
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* @queue: requests queue
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* @lock: lock to pxa_ep data (queues and stats)
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* @enabled: true when endpoint enabled (not stopped by gadget layer)
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* @in_handle_ep: number of recursions of handle_ep() function
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* Prevents deadlocks or infinite recursions of types :
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* irq->handle_ep()->req_done()->req.complete()->pxa_ep_queue()->handle_ep()
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* or
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* pxa_ep_queue()->handle_ep()->req_done()->req.complete()->pxa_ep_queue()
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* @idx: endpoint index (1 => epA, 2 => epB, ..., 24 => epX)
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* @name: endpoint name (for trace/debug purpose)
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* @dir_in: 1 if IN endpoint, 0 if OUT endpoint
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@ -346,6 +351,7 @@ struct pxa_ep {
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spinlock_t lock; /* Protects this structure */
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/* (queues, stats) */
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unsigned enabled:1;
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unsigned in_handle_ep:1;
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unsigned idx:5;
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char *name;
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