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=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 03101C388F7 for ; Sat, 31 Oct 2020 11:36:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB91520791 for ; Sat, 31 Oct 2020 11:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604144191; bh=QGqN73TlyPV9Esx6Em0+u7wW5ISeEhOcwbfgUOltegY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=G8mVqNF3yilRE2bRZFn2H/nlz45nsSIAuWtj0YNSfrMVW94DuW/r4FsOyV+F2TfeX NR6S34HUiEhxeamVfx6gVsrNaFj0OOzSkupUPcnBp5N4eV3kdnIjjHROpctMPxbDma FKIJe0ieTgzgfuEnQOfvXQmUcoA9JPhMGJg8DlpE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727195AbgJaLg3 (ORCPT ); Sat, 31 Oct 2020 07:36:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:34442 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727168AbgJaLgU (ORCPT ); Sat, 31 Oct 2020 07:36:20 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BB6DC22228; Sat, 31 Oct 2020 11:36:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604144180; bh=QGqN73TlyPV9Esx6Em0+u7wW5ISeEhOcwbfgUOltegY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Eo5dTWW3F0LSjlDtBbgmFY/ub2oPyyfWezmHaaMldfaqG365Ho0LTNUgy0ynvw2kx 9cRY3ToS7d0cm+IxOU6tiNIy1+2ozvcHxBD9YfmuIbXU3c1h9XRXUlaZ9uSsdT3CxX GzK94NjGFVpHA2A7kofkmGcbj9hFofVp8dVGi9CY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jia-Ju Bai , Christian Lamparter , Kalle Valo Subject: [PATCH 5.4 36/49] p54: avoid accessing the data mapped to streaming DMA Date: Sat, 31 Oct 2020 12:35:32 +0100 Message-Id: <20201031113457.183530530@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201031113455.439684970@linuxfoundation.org> References: <20201031113455.439684970@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jia-Ju Bai commit 478762855b5ae9f68fa6ead1edf7abada70fcd5f upstream. In p54p_tx(), skb->data is mapped to streaming DMA on line 337: mapping = pci_map_single(..., skb->data, ...); Then skb->data is accessed on line 349: desc->device_addr = ((struct p54_hdr *)skb->data)->req_id; This access may cause data inconsistency between CPU cache and hardware. To fix this problem, ((struct p54_hdr *)skb->data)->req_id is stored in a local variable before DMA mapping, and then the driver accesses this local variable instead of skb->data. Cc: Signed-off-by: Jia-Ju Bai Acked-by: Christian Lamparter Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20200802132949.26788-1-baijiaju@tsinghua.edu.cn Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/intersil/p54/p54pci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/net/wireless/intersil/p54/p54pci.c +++ b/drivers/net/wireless/intersil/p54/p54pci.c @@ -329,10 +329,12 @@ static void p54p_tx(struct ieee80211_hw struct p54p_desc *desc; dma_addr_t mapping; u32 idx, i; + __le32 device_addr; spin_lock_irqsave(&priv->lock, flags); idx = le32_to_cpu(ring_control->host_idx[1]); i = idx % ARRAY_SIZE(ring_control->tx_data); + device_addr = ((struct p54_hdr *)skb->data)->req_id; mapping = pci_map_single(priv->pdev, skb->data, skb->len, PCI_DMA_TODEVICE); @@ -346,7 +348,7 @@ static void p54p_tx(struct ieee80211_hw desc = &ring_control->tx_data[i]; desc->host_addr = cpu_to_le32(mapping); - desc->device_addr = ((struct p54_hdr *)skb->data)->req_id; + desc->device_addr = device_addr; desc->len = cpu_to_le16(skb->len); desc->flags = 0;