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Subject: Re: [PATCH 1/6] mm: mmap: fix fput in error path
To:     Jason Gunthorpe <jgg@ziepe.ca>,
        Andrew Morton <akpm@linux-foundation.org>
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        airlied@redhat.com, daniel@ffwll.ch, sumit.semwal@linaro.org,
        willy@infradead.org, jhubbard@nvidia.com,
        Miaohe Lin <linmiaohe@huawei.com>
References: <20201009150342.1979-1-christian.koenig@amd.com>
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 <20201009222509.GC5177@ziepe.ca>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <ckoenig.leichtzumerken@gmail.com>
Message-ID: <666ef8f3-6299-3c0b-6ebb-04e957a115a1@gmail.com>
Date:   Mon, 12 Oct 2020 10:13:14 +0200
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Am 10.10.20 um 00:25 schrieb Jason Gunthorpe:
> On Fri, Oct 09, 2020 at 03:04:20PM -0700, Andrew Morton wrote:
>> On Fri,  9 Oct 2020 17:03:37 +0200 "Christian König" <ckoenig.leichtzumerken@gmail.com> wrote:
>>
>>> Patch "495c10cc1c0c CHROMIUM: dma-buf: restore args..."
>>> adds a workaround for a bug in mmap_region.
>>>
>>> As the comment states ->mmap() callback can change
>>> vma->vm_file and so we might call fput() on the wrong file.
>>>
>>> Revert the workaround and proper fix this in mmap_region.
>>>
>> Doesn't this patch series address the same thing as
>> https://lkml.kernel.org/r/20200916090733.31427-1-linmiaohe@huawei.com?
> Same basic issue, looks like both of these patches should be combined
> to plug it fully.

Yes, agree completely.

It's a different error path, but we need to fix both occasions.

Christian.

>
> Jason