linux-kernel - Re: linux-next: build failure after merge of the drm tree

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: <20200928113415.GA555@lst.de>
Date:   Mon, 28 Sep 2020 13:34:15 +0200
From:   Christoph Hellwig <hch@....de>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     Christoph Hellwig <hch@....de>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Dave Airlie <airlied@...ux.ie>,
        DRI <dri-devel@...ts.freedesktop.org>,
        Linux Next Mailing List <linux-next@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: linux-next: build failure after merge of the drm tree

On Mon, Sep 28, 2020 at 12:15:56PM +0200, Paul Cercueil wrote:
> Hi Christoph,
>
> Le lun. 28 sept. 2020 à 8:04, Christoph Hellwig <hch@....de> a écrit :
>> On Mon, Sep 28, 2020 at 01:54:05PM +1000, Stephen Rothwell wrote:
>>>  Hi all,
>>>
>>>  After merging the drm tree, today's linux-next build (x86_64 
>>> allmodconfig)
>>>  failed like this:
>>
>> The driver needs to switch do dma_alloc_noncoherent + dma_sync_single*
>> like the other drivers converted in the dma tree.  Paul, let me know if
>> you have any questions.
>
> I don't dma_alloc* anything, DRM core does. I use the 
> DMA_ATTR_NON_CONSISTENT attr with dma_mmap_attrs(). Is there a replacement 
> for that?

dma_mmap_attrs can only be used on allocations from dma_mmap_attrs with
the same attrs.  As there is no allocation using DMA_ATTR_NON_CONSISTENT
in the drm core, something looks very fishy here.

Where does the allocation you try to mmap come from?  All the allocations
in drivers/gpu/drm/drm_gem_cma_helper.c seems to use dma_alloc_wc (aka
dma_allloc_attrs with the DMA_ATTR_WRITE_COMBINE flag).