From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Date: Wed, 18 Apr 2018 09:13:10 +0000 Subject: Re: [PATCH] sh: mm: Fix unprotected access to struct device Message-Id: <75621aa6-1fe9-2049-fc70-fd6d542c7307@cogentembedded.com> List-Id: References: <1523972123-5700-1-git-send-email-jacopo+renesas@jmondi.org> In-Reply-To: <1523972123-5700-1-git-send-email-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Jacopo Mondi , ysato@users.sourceforge.jp, dalias@libc.org, thomas.petazzoni@free-electrons.com, robin.murphy@arm.com Cc: geert@linux-m68k.org, linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org Hello! On 4/17/2018 4:35 PM, Jacopo Mondi wrote: > With commit ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping > operations observe dev->dma_pfn_offset") the generic DMA allocation > function on which the SH 'dma_alloc_coherent()' function relies on, > access the 'dma_pfn_offset' field of struct device. > > Unfortunately the 'dma_generic_alloc_coherent()' function is called from > several places with a NULL struct device argument, halting the CPU > during the boot process. > > This patch fixes the issue protecting access to dev->dma_pfn_offset, > with a trivial check for validity. It also passes a valid 'struct device' > in the 'platform_resource_setup_memory' function which is the main user > of 'dma_alloc_coherent()', and inserting a WARN_ON() check to make future > (and existing) bogus users of this function they're should provide a valid > 'struct device' whenever possible. > > Fixes: ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping operations observe dev->dma_pfn_offset") > Signed-off-by: Jacopo Mondi > --- > arch/sh/mm/consistent.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/sh/mm/consistent.c b/arch/sh/mm/consistent.c > index 8ce9869..b257155 100644 > --- a/arch/sh/mm/consistent.c > +++ b/arch/sh/mm/consistent.c [...] > @@ -69,9 +73,14 @@ void dma_generic_free_coherent(struct device *dev, size_t size, > unsigned long attrs) > { > int order = get_order(size); > - unsigned long pfn = (dma_handle >> PAGE_SHIFT) + dev->dma_pfn_offset; > + unsigned long pfn = (dma_handle >> PAGE_SHIFT); Parens no longer needed... [...] MBR, Sergei From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753202AbeDRJNQ (ORCPT ); Wed, 18 Apr 2018 05:13:16 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:38404 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752749AbeDRJNO (ORCPT ); Wed, 18 Apr 2018 05:13:14 -0400 X-Google-Smtp-Source: AIpwx49eSnTZC9dL/ZrS1h1ebVxLHArk9Nn7Elm/K40ScveG7NE0VdJpQT2OrycH9lEWB/2BcTFYeA== Subject: Re: [PATCH] sh: mm: Fix unprotected access to struct device To: Jacopo Mondi , ysato@users.sourceforge.jp, dalias@libc.org, thomas.petazzoni@free-electrons.com, robin.murphy@arm.com Cc: geert@linux-m68k.org, linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org References: <1523972123-5700-1-git-send-email-jacopo+renesas@jmondi.org> From: Sergei Shtylyov Message-ID: <75621aa6-1fe9-2049-fc70-fd6d542c7307@cogentembedded.com> Date: Wed, 18 Apr 2018 12:13:10 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1523972123-5700-1-git-send-email-jacopo+renesas@jmondi.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! On 4/17/2018 4:35 PM, Jacopo Mondi wrote: > With commit ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping > operations observe dev->dma_pfn_offset") the generic DMA allocation > function on which the SH 'dma_alloc_coherent()' function relies on, > access the 'dma_pfn_offset' field of struct device. > > Unfortunately the 'dma_generic_alloc_coherent()' function is called from > several places with a NULL struct device argument, halting the CPU > during the boot process. > > This patch fixes the issue protecting access to dev->dma_pfn_offset, > with a trivial check for validity. It also passes a valid 'struct device' > in the 'platform_resource_setup_memory' function which is the main user > of 'dma_alloc_coherent()', and inserting a WARN_ON() check to make future > (and existing) bogus users of this function they're should provide a valid > 'struct device' whenever possible. > > Fixes: ce88313069c36eef80f21fd7 ("arch/sh: make the DMA mapping operations observe dev->dma_pfn_offset") > Signed-off-by: Jacopo Mondi > --- > arch/sh/mm/consistent.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/sh/mm/consistent.c b/arch/sh/mm/consistent.c > index 8ce9869..b257155 100644 > --- a/arch/sh/mm/consistent.c > +++ b/arch/sh/mm/consistent.c [...] > @@ -69,9 +73,14 @@ void dma_generic_free_coherent(struct device *dev, size_t size, > unsigned long attrs) > { > int order = get_order(size); > - unsigned long pfn = (dma_handle >> PAGE_SHIFT) + dev->dma_pfn_offset; > + unsigned long pfn = (dma_handle >> PAGE_SHIFT); Parens no longer needed... [...] MBR, Sergei