From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030224Ab2I1TBp (ORCPT ); Fri, 28 Sep 2012 15:01:45 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:45270 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030209Ab2I1TBl (ORCPT ); Fri, 28 Sep 2012 15:01:41 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , alan@lxorguk.ukuu.org.uk, Michael Grzeschik , Marc Kleine-Budde , Alexander Shishkin Subject: [ 157/262] usb: chipidea: udc: dont stall endpoint if request list is empty in isr_tr_complete_low Date: Fri, 28 Sep 2012 11:51:26 -0700 Message-Id: <20120928183016.519334717@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120928182957.993484211@linuxfoundation.org> References: <20120928182957.993484211@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Grzeschik commit db89960e50f45274c07dc60926b5a49489b8a7a0 upstream. When attaching an imx28 or imx53 in USB gadget mode to a Windows host and starting a rndis connection we see this message every 4-10 seconds: g_ether gadget: high speed config #2: RNDIS Analysis shows that each time this message is printed, the rndis connection is re-establish due to a reset because of a stalled endpoint (ep 0, dir 1). The endpoint is stalled because the reqeust complete bit on that endpoint is set, but in isr_tr_complete_low() the endpoint request list (mEp->qh.queue) is empty. This patch removed this check, because the code doesn't take the following situation into account: The loop over all endpoints in isr_tr_complete_handler() will call ep_nuke() on both ep0/dir0 and ep/dir1 in the first loop. Pending reqeusts will be flushed and completed here. There seems to be a race condition, the request is nuked, but the request complete bit will be set, too. The subsequent check (in ep0/dir1's loop cycle) for endpoint request list (mEp->qh.queue) empty will fail. Both other mainline chipidea drivers (mv_udc_core.c and fsl_udc_core.c) don't have this check. Signed-off-by: Michael Grzeschik Signed-off-by: Marc Kleine-Budde Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/chipidea/udc.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) --- a/drivers/usb/chipidea/udc.c +++ b/drivers/usb/chipidea/udc.c @@ -771,10 +771,7 @@ __acquires(mEp->lock) { struct ci13xxx_req *mReq, *mReqTemp; struct ci13xxx_ep *mEpTemp = mEp; - int uninitialized_var(retval); - - if (list_empty(&mEp->qh.queue)) - return -EINVAL; + int retval = 0; list_for_each_entry_safe(mReq, mReqTemp, &mEp->qh.queue, queue) {