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=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 14C3CC04AAD for ; Wed, 8 May 2019 22:33:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7ED8216C4 for ; Wed, 8 May 2019 22:33:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727407AbfEHWdf (ORCPT ); Wed, 8 May 2019 18:33:35 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54335 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726163AbfEHWdf (ORCPT ); Wed, 8 May 2019 18:33:35 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1hOV7y-0001Rt-83; Wed, 08 May 2019 22:33:30 +0000 From: Colin King To: Dan Williams , Vinod Koul , Huang Shijie , dmaengine@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] dma: dw-axi-dmac: fix null dereference when pointer first is null Date: Wed, 8 May 2019 23:33:29 +0100 Message-Id: <20190508223329.26796-1-colin.king@canonical.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King In the unlikely event that axi_desc_get returns a null desc in the very first iteration of the while-loop the error exit path ends up calling axi_desc_put on a null pointer 'first' and this causes a null pointer dereference. Fix this by adding a null check on pointer 'first' before calling axi_desc_put. Addresses-Coverity: ("Explicit null dereference") fixes: 1fe20f1b8454 ("dmaengine: Introduce DW AXI DMAC driver") Signed-off-by: Colin Ian King --- drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c index b2ac1d2c5b86..a1ce307c502f 100644 --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c @@ -512,7 +512,8 @@ dma_chan_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dst_adr, return vchan_tx_prep(&chan->vc, &first->vd, flags); err_desc_get: - axi_desc_put(first); + if (first) + axi_desc_put(first); return NULL; } -- 2.20.1