linux-kernel - Re: Regression due to d98849aff879 (dma-direct: handle DMA_ATTR_NO_KERNEL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190806154602.GB25050@lst.de>
Date:   Tue, 6 Aug 2019 17:46:02 +0200
From:   Christoph Hellwig <hch@....de>
To:     "Lendacky, Thomas" <Thomas.Lendacky@....com>
Cc:     Lucas Stach <l.stach@...gutronix.de>,
        Christoph Hellwig <hch@....de>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
        Halil Pasic <pasic@...ux.ibm.com>
Subject: Re: Regression due to d98849aff879 (dma-direct: handle
 DMA_ATTR_NO_KERNEL_MAPPING in common code)

On Tue, Aug 06, 2019 at 02:18:49PM +0000, Lendacky, Thomas wrote:
> I think you need to keep everything inside the original if statement since
> the caller is expecting a page pointer to be returned in this case and not
> the page_address() which is returned when the DMA_ATTR_NO_KERNEL_MAPPING
> is not present.

DMA_ATTR_NO_KERNEL_MAPPING is defined to return an opaque cookie,
which just happens to be a page pointer.  So if we fix up the free side
as pointed out by Lucas we should be fine.