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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 27C83C33CA2 for ; Fri, 10 Jan 2020 11:56:42 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E849B2072A for ; Fri, 10 Jan 2020 11:56:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="un5HZx/7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E849B2072A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=8qlTQ4j0JT5Z55ZE9H5sXs9kYmvdZf6uSpQix2QYnME=; b=un5HZx/7ypigoCpPsHDfJgR+YH 2PI/I9Bg+Q1TxmZLMMiKtGrx7wMUZgRU95CNUujsp9NB3RN+jb7aMT0bTdLcmbMTVDtgh4VmuXsoL 9Qb2faWrIp/xZbPxexADfX91eCpthxqbgFGOzSBpnryKyViV3YARPLFXAVtaAXI/MLMFU4dW/amlM +dlXli/ouCAJO7UKIbAIIOGVvPYsr6BV2BaaKDpBdYTisIkolI7VsEcJ+iZkjwEH75NCjoNkK6huj lrG0PjVBNVzwkB4t2X2Z7mYDsXoeZnTSQifWqj828DqIUrC3KzFvii0Q6RiynaLWs6ajsbU+6m3yb O/yYdMJQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ipsu2-00011b-Tk; Fri, 10 Jan 2020 11:56:34 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ipsrz-0006cJ-QL for linux-arm-kernel@lists.infradead.org; Fri, 10 Jan 2020 11:54:32 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 62F3F13A1; Fri, 10 Jan 2020 03:54:27 -0800 (PST) Received: from donnerap.arm.com (donnerap.cambridge.arm.com [10.1.197.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4A3493F534; Fri, 10 Jan 2020 03:54:26 -0800 (PST) From: Andre Przywara To: "David S . Miller" , Radhey Shyam Pandey Subject: [PATCH 03/14] net: axienet: Fix DMA descriptor cleanup path Date: Fri, 10 Jan 2020 11:54:04 +0000 Message-Id: <20200110115415.75683-4-andre.przywara@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200110115415.75683-1-andre.przywara@arm.com> References: <20200110115415.75683-1-andre.przywara@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200110_035428_113946_C1131C5E X-CRM114-Status: GOOD ( 13.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Robert Hancock , netdev@vger.kernel.org, Michal Simek , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org When axienet_dma_bd_init() bails out during the initialisation process, it might do so with parts of the structure already allocated and initialised, while other parts have not been touched yet. Before returning in this case, we call axienet_dma_bd_release(), which does not take care of this corner case. This is most obvious by the first loop happily dereferencing lp->rx_bd_v, which we actually check to be non NULL *afterwards*. Make sure we only unmap or free already allocated structures, by: - directly returning with -ENOMEM if nothing has been allocated at all - checking for lp->rx_bd_v to be non-NULL *before* using it - only unmapping allocated DMA RX regions This avoids NULL pointer dereferences when initialisation fails. Signed-off-by: Andre Przywara --- .../net/ethernet/xilinx/xilinx_axienet_main.c | 43 ++++++++++++------- 1 file changed, 28 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 97482cf093ce..7e90044cf2d9 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -160,24 +160,37 @@ static void axienet_dma_bd_release(struct net_device *ndev) int i; struct axienet_local *lp = netdev_priv(ndev); + /* If we end up here, tx_bd_v must have been DMA allocated. */ + dma_free_coherent(ndev->dev.parent, + sizeof(*lp->tx_bd_v) * lp->tx_bd_num, + lp->tx_bd_v, + lp->tx_bd_p); + + if (!lp->rx_bd_v) + return; + for (i = 0; i < lp->rx_bd_num; i++) { - dma_unmap_single(ndev->dev.parent, lp->rx_bd_v[i].phys, - lp->max_frm_size, DMA_FROM_DEVICE); + /* A NULL skb means this descriptor has not been initialised + * at all. + */ + if (!lp->rx_bd_v[i].skb) + break; + dev_kfree_skb(lp->rx_bd_v[i].skb); - } - if (lp->rx_bd_v) { - dma_free_coherent(ndev->dev.parent, - sizeof(*lp->rx_bd_v) * lp->rx_bd_num, - lp->rx_bd_v, - lp->rx_bd_p); - } - if (lp->tx_bd_v) { - dma_free_coherent(ndev->dev.parent, - sizeof(*lp->tx_bd_v) * lp->tx_bd_num, - lp->tx_bd_v, - lp->tx_bd_p); + /* For each descriptor, we programmed cntrl with the (non-zero) + * descriptor size, after it had been successfully allocated. + * So a non-zero value in there means we need to unmap it. + */ + if (lp->rx_bd_v[i].cntrl) + dma_unmap_single(ndev->dev.parent, lp->rx_bd_v[i].phys, + lp->max_frm_size, DMA_FROM_DEVICE); } + + dma_free_coherent(ndev->dev.parent, + sizeof(*lp->rx_bd_v) * lp->rx_bd_num, + lp->rx_bd_v, + lp->rx_bd_p); } /** @@ -207,7 +220,7 @@ static int axienet_dma_bd_init(struct net_device *ndev) sizeof(*lp->tx_bd_v) * lp->tx_bd_num, &lp->tx_bd_p, GFP_KERNEL); if (!lp->tx_bd_v) - goto out; + return -ENOMEM; lp->rx_bd_v = dma_alloc_coherent(ndev->dev.parent, sizeof(*lp->rx_bd_v) * lp->rx_bd_num, -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel