[PATCH 1/6] mm: mmap: fix fput in error path

[linmiaohe]

Jason Gunthorpe <jgg at ziepe.ca> wrote:
> 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 at 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.
>
>Jason 

I think so too. Both of these patches fix the fput at possible wrong @file due to ->mmap() callback can change vma->vm_file.