From patchwork Mon Jun 13 15:07:33 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 102238 Delivered-To: patch@linaro.org Received: by 10.140.106.246 with SMTP id e109csp1591327qgf; Mon, 13 Jun 2016 08:08:16 -0700 (PDT) X-Received: by 10.66.253.38 with SMTP id zx6mr22225065pac.19.1465830496506; Mon, 13 Jun 2016 08:08:16 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id sa6si16389384pac.54.2016.06.13.08.08.16; Mon, 13 Jun 2016 08:08:16 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423890AbcFMPID (ORCPT + 30 others); Mon, 13 Jun 2016 11:08:03 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:53774 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422810AbcFMPIA (ORCPT ); Mon, 13 Jun 2016 11:08:00 -0400 Received: from wuerfel.lan. ([78.42.132.4]) by mrelayeu.kundenserver.de (mreue004) with ESMTPA (Nemesis) id 0M6yZd-1bOen60x7t-00wpdy; Mon, 13 Jun 2016 17:07:13 +0200 From: Arnd Bergmann To: Vinod Koul Cc: Arnd Bergmann , Dan Williams , Michal Simek , =?utf-8?q?S=C3=B6ren_Brinkmann?= , Kedareswara rao Appana , Laurent Pinchart , dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] dma: xilinx-vdma: add some sanity checks Date: Mon, 13 Jun 2016 17:07:33 +0200 Message-Id: <1465830523-2484498-1-git-send-email-arnd@arndb.de> X-Mailer: git-send-email 2.7.0 X-Provags-ID: V03:K0:R7pkTIgePAUVBaZtZUW5I19UAsTzBLJ0SYXQYdsDlKTihH6mSPM TuBtRuMFHtyUlaJxbvsr4iYoo+LdCZZKBiuEXzNC8q0D4sBPUNyRxIUFVFuxulT6LryidwC QQyTAsPL4A0vE55+bqYA103ATXzbOTm6bLFkSWvdwXEgUFzMjD3OMZPkypfEaehwxFNuvYY w8sCsI/gnsETToZkIdfng== X-UI-Out-Filterresults: notjunk:1; V01:K0:5PA49ccAd/w=:SNk/dHXqDaDxeYN8TlueEe FpMlIq24w2DF/+fUEu04MdosJrUZC6eRoYiX8yx4q36WXcTIi+fHmNvKKzl1sjABlaWCETz/Z lP9JSrtj0lzJ+WIfIqH3j1Y+VjYEJNalkBgq+j5w0TmHdnI5bnO+G5QvMxlnyoXh28ka3dTMx OOZ7SvB0e343GqWzTuIqxvlZplYbagSq0/qTJJFKP8zeipesW+zw8r/rAfBdnSmo0DJGMS5ll 3+wFmJBmKxJ+zjdJilczENR6M/PJ7i/aXuWGujLAcyAYb+jJoVVQ9TIzqXRF0VqwpmA+WNWci YfkWzKmPfO6iKBFZtLGBZa2vuQEsfM7aCMQeGDopJE6yRmLFlk16274UfxIkHlZKSrRiGAFlv I7hC4fue1LkqpOkkjTQVKBEpBMjaRU11IQRHiTwSM0D/aeklwEjLaEqsJVvwwInGnO3O533sm d7ag+eQsSFjZeCJTUwG9mqVEfKsilmvZDSHbkghDpTF7g6F43oFTn+QJmQlJ1AlqLcVcIFSkg yU/wl7KjpjCl04LIK79C8MoHWzXXCZCClzs5YZHjurpEVGGz/VtrrN/bMA7jt/RbReaCIrxZN EJcmSnp3px37RCj30DylWqhPLvQ5VqQiQT0dItsSV7Bhl7ygYeDjsyTDxSZXyfjr/yTzc3xWc oDO1TrK3SKzEWr3FwHovMQp371OQNbsOs+dc2VNqGN6J+LlQ0pBoMhp6GHIhLhoFdLqQ= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The newly added xilinx_dma_prep_dma_cyclic function sometimes causes a gcc warning about the use of the segment function in case we never run into the inner loop of the function: dma/xilinx/xilinx_vdma.c: In function 'xilinx_dma_prep_dma_cyclic': dma/xilinx/xilinx_vdma.c:1808:23: error: 'segment' may be used uninitialized in this function [-Werror=maybe-uninitialized] segment->hw.control |= XILINX_DMA_BD_SOP; This can only happen if the period len is zero (which would cause other problems earlier), or if the buffer is shorter than a period. Neither of them should ever happen, but by adding an explicit check for these two cases, we can abort in a more controlled way, and the compiler is able to see that we never use uninitialized data. Signed-off-by: Arnd Bergmann --- drivers/dma/xilinx/xilinx_vdma.c | 6 ++++++ 1 file changed, 6 insertions(+) -- 2.7.0 diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c index 0f5b38a0e46f..2ac3253bc823 100644 --- a/drivers/dma/xilinx/xilinx_vdma.c +++ b/drivers/dma/xilinx/xilinx_vdma.c @@ -1745,8 +1745,14 @@ static struct dma_async_tx_descriptor *xilinx_dma_prep_dma_cyclic( int i; u32 reg; + if (!period_len) + return NULL; + num_periods = buf_len / period_len; + if (!num_periods) + return NULL; + if (!is_slave_direction(direction)) return NULL;