From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753504AbdDDLMB (ORCPT ); Tue, 4 Apr 2017 07:12:01 -0400 Received: from foss.arm.com ([217.140.101.70]:42726 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751101AbdDDLK6 (ORCPT ); Tue, 4 Apr 2017 07:10:58 -0400 Subject: Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask To: Sricharan R , will.deacon@arm.com, joro@8bytes.org, lorenzo.pieralisi@arm.com, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, m.szyprowski@samsung.com, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, tn@semihalf.com, hanjun.guo@linaro.org, okaya@codeaurora.org, robh+dt@kernel.org, frowand.list@gmail.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, lenb@kernel.org, catalin.marinas@arm.com, arnd@arndb.de, linux-arch@vger.kernel.org, gregkh@linuxfoundation.org References: <1489086061-9356-1-git-send-email-sricharan@codeaurora.org> <1491301105-5274-1-git-send-email-sricharan@codeaurora.org> <1491301105-5274-7-git-send-email-sricharan@codeaurora.org> From: Robin Murphy Message-ID: <906032bd-8f3d-f34c-7c0f-0222c39fb552@arm.com> Date: Tue, 4 Apr 2017 12:10:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <1491301105-5274-7-git-send-email-sricharan@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/04/17 11:18, Sricharan R wrote: > Size of the dma-range is calculated as coherent_dma_mask + 1 > and passed to arch_setup_dma_ops further. It overflows when > the coherent_dma_mask is set for full 64 bits 0xFFFFFFFFFFFFFFFF, > resulting in size getting passed as 0 wrongly. Fix this by > passsing in max(mask, mask + 1). Note that in this case > when the mask is set to full 64bits, we will be passing the mask > itself to arch_setup_dma_ops instead of the size. The real fix > for this should be to make arch_setup_dma_ops receive the > mask and handle it, to be done in the future. Agreed; in the meantime, this fix is neat and robust enough. Reviewed-by: Robin Murphy > Signed-off-by: Sricharan R > --- > drivers/of/device.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/of/device.c b/drivers/of/device.c > index c17c19d..c2ae6bb 100644 > --- a/drivers/of/device.c > +++ b/drivers/of/device.c > @@ -107,7 +107,7 @@ void of_dma_configure(struct device *dev, struct device_node *np) > ret = of_dma_get_range(np, &dma_addr, &paddr, &size); > if (ret < 0) { > dma_addr = offset = 0; > - size = dev->coherent_dma_mask + 1; > + size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); > } else { > offset = PFN_DOWN(paddr - dma_addr); > dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset); >