From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78343C282CE for ; Mon, 22 Apr 2019 19:59:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43031204EC for ; Mon, 22 Apr 2019 19:59:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555963163; bh=dLP6w9/tALpsZnV0WfYXd/WRDaIRYd6Lb5TXRLJA7Co=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MjzA/HoB8sPwTaZ3PXa++eTgnItjaGPpLq+62MG7khQ6n7kFXqZWPHFeqxlM805JZ Qd0Jdh4aAZMZ8vUB6mgrC29kEAZTRD4kbMbhE1N9A3oGWHJpOtMqzK7RGF0wA9Hc6L yg81y1TuBYW7BJ7LNhhO/i6ciKnZk+KuD/kYApF8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731822AbfDVT7W (ORCPT ); Mon, 22 Apr 2019 15:59:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:50660 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729869AbfDVTro (ORCPT ); Mon, 22 Apr 2019 15:47:44 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1B87321904; Mon, 22 Apr 2019 19:47:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555962463; bh=dLP6w9/tALpsZnV0WfYXd/WRDaIRYd6Lb5TXRLJA7Co=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fiqr7zl5DPR+Chr6uOYRTDpqbLR3FkVleKeyxhwMZRfP527SQ+U3GsWcpNF28TnTa VOLEh5vi0fauHSvrmOARQmumpBbvGu7PhH65NAieke+xhU7TVa7S5El8Ny1mQJlxaB pA44pYhw+5QwMYMcQHqeme3Fq7cMe1LcpUneByRk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Guido Kiener , Guido Kiener , Felipe Balbi , Sasha Levin , linux-usb@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 10/43] usb: gadget: net2280: Fix overrun of OUT messages Date: Mon, 22 Apr 2019 15:46:54 -0400 Message-Id: <20190422194727.12495-10-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190422194727.12495-1-sashal@kernel.org> References: <20190422194727.12495-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guido Kiener [ Upstream commit 9d6a54c1430647355a5e23434881b2ca3d192b48 ] The OUT endpoint normally blocks (NAK) subsequent packets when a short packet was received and returns an incomplete queue entry to the gadget driver. Thereby the gadget driver can detect a short packet when reading queue entries with a length that is not equal to a multiple of packet size. The start_queue() function enables receiving OUT packets regardless of the content of the OUT FIFO. This results in a race: With the current code, it's possible that the "!ep->is_in && (readl(&ep->regs->ep_stat) & BIT(NAK_OUT_PACKETS))" test in start_dma() will fail, then a short packet will be received, and then start_queue() will call stop_out_naking(). That's what we don't want (OUT naking gets turned off while there is data in the FIFO) because then the next driver request might receive a mixture of old and new packets. With the patch, this race can't occur because the FIFO's state is tested after we know that OUT naking is already turned on, and OUT naking is stopped only when both of the conditions are met. This ensures that all received data is delivered to the gadget driver, which can detect a short packet now before new packets are appended to the last short packet. Acked-by: Alan Stern Signed-off-by: Guido Kiener Signed-off-by: Felipe Balbi Signed-off-by: Sasha Levin (Microsoft) --- drivers/usb/gadget/udc/net2280.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/usb/gadget/udc/net2280.c b/drivers/usb/gadget/udc/net2280.c index 9cbb061582a7..a071ab0c163b 100644 --- a/drivers/usb/gadget/udc/net2280.c +++ b/drivers/usb/gadget/udc/net2280.c @@ -870,9 +870,6 @@ static void start_queue(struct net2280_ep *ep, u32 dmactl, u32 td_dma) (void) readl(&ep->dev->pci->pcimstctl); writel(BIT(DMA_START), &dma->dmastat); - - if (!ep->is_in) - stop_out_naking(ep); } static void start_dma(struct net2280_ep *ep, struct net2280_request *req) @@ -911,6 +908,7 @@ static void start_dma(struct net2280_ep *ep, struct net2280_request *req) writel(BIT(DMA_START), &dma->dmastat); return; } + stop_out_naking(ep); } tmp = dmactl_default; -- 2.19.1