Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752526AbYLYOPq (ORCPT ); Thu, 25 Dec 2008 09:15:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751931AbYLYOPJ (ORCPT ); Thu, 25 Dec 2008 09:15:09 -0500 Received: from rtsoft3.corbina.net ([85.21.88.6]:53981 "EHLO buildserver.ru.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751893AbYLYOPH (ORCPT ); Thu, 25 Dec 2008 09:15:07 -0500 Date: Thu, 25 Dec 2008 17:15:05 +0300 From: Anton Vorontsov To: Greg Kroah-Hartman Cc: Andrew Morton , Alan Stern , David Brownell , Timur Tabi , Li Yang , linux-usb@vger.kernel.org, linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/6] USB: fsl_qe_udc: Fix recursive locking bug in ch9getstatus() Message-ID: <20081225141505.GB6786@oksana.dev.rtsoft.ru> References: <20081225141402.GA30689@oksana.dev.rtsoft.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=windows-1251 Content-Disposition: inline In-Reply-To: <20081225141402.GA30689@oksana.dev.rtsoft.ru> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3007 Lines: 93 The call chain is this: qe_udc_irq() <- grabs the udc->lock spinlock rx_irq() qe_ep0_rx() ep0_setup_handle() setup_received_handle() ch9getstatus() qe_ep_queue() <- tries to grab the udc->lock again It seems unsafe to temporarily drop the lock in the ch9getstatus(), so to fix that bug the lock-less __qe_ep_queue() function implemented and used by the ch9getstatus(). Signed-off-by: Anton Vorontsov Acked-by: David Brownell --- drivers/usb/gadget/fsl_qe_udc.c | 26 ++++++++++++++++++-------- 1 files changed, 18 insertions(+), 8 deletions(-) diff --git a/drivers/usb/gadget/fsl_qe_udc.c b/drivers/usb/gadget/fsl_qe_udc.c index db6fe04..2677c9e 100644 --- a/drivers/usb/gadget/fsl_qe_udc.c +++ b/drivers/usb/gadget/fsl_qe_udc.c @@ -1681,14 +1681,11 @@ static void qe_free_request(struct usb_ep *_ep, struct usb_request *_req) kfree(req); } -/* queues (submits) an I/O request to an endpoint */ -static int qe_ep_queue(struct usb_ep *_ep, struct usb_request *_req, - gfp_t gfp_flags) +static int __qe_ep_queue(struct usb_ep *_ep, struct usb_request *_req) { struct qe_ep *ep = container_of(_ep, struct qe_ep, ep); struct qe_req *req = container_of(_req, struct qe_req, req); struct qe_udc *udc; - unsigned long flags; int reval; udc = ep->udc; @@ -1732,7 +1729,7 @@ static int qe_ep_queue(struct usb_ep *_ep, struct usb_request *_req, list_add_tail(&req->queue, &ep->queue); dev_vdbg(udc->dev, "gadget have request in %s! %d\n", ep->name, req->req.length); - spin_lock_irqsave(&udc->lock, flags); + /* push the request to device */ if (ep_is_in(ep)) reval = ep_req_send(ep, req); @@ -1748,11 +1745,24 @@ static int qe_ep_queue(struct usb_ep *_ep, struct usb_request *_req, if (ep->dir == USB_DIR_OUT) reval = ep_req_receive(ep, req); - spin_unlock_irqrestore(&udc->lock, flags); - return 0; } +/* queues (submits) an I/O request to an endpoint */ +static int qe_ep_queue(struct usb_ep *_ep, struct usb_request *_req, + gfp_t gfp_flags) +{ + struct qe_ep *ep = container_of(_ep, struct qe_ep, ep); + struct qe_udc *udc = ep->udc; + unsigned long flags; + int ret; + + spin_lock_irqsave(&udc->lock, flags); + ret = __qe_ep_queue(_ep, _req); + spin_unlock_irqrestore(&udc->lock, flags); + return ret; +} + /* dequeues (cancels, unlinks) an I/O request from an endpoint */ static int qe_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req) { @@ -2008,7 +2018,7 @@ static void ch9getstatus(struct qe_udc *udc, u8 request_type, u16 value, udc->ep0_dir = USB_DIR_IN; /* data phase */ - status = qe_ep_queue(&ep->ep, &req->req, GFP_ATOMIC); + status = __qe_ep_queue(&ep->ep, &req->req); if (status == 0) return; -- 1.5.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/