Re: [PATCH] dmabuf: use spinlock to access dmabuf->name

[Charan Teja Kalla <charante@codeaurora.org>]

On 6/17/2020 1:51 PM, David Laight wrote:
> From: Charan Teja Kalla
>> Sent: 17 June 2020 07:29
> ...
>>>> If name is freed you will copy garbage, but the only way
>>>> for that to happen is that _set_name or _release have to be called
>>>> at just the right time.
>>>>
>>>> And the above would probably only be an issue if the set_name
>>>> was called, so you will get NULL or a real name.
>>
>> And there exists a use-after-free to avoid which requires the lock. Say
>> that memcpy() in dmabuffs_dname is in progress and in parallel _set_name
>> will free the same buffer that memcpy is operating on.
> 
> If the name is being looked at while the item is being freed
> you almost certainly have much bigger problems that just
> the name being a 'junk' pointer.

True, thus needs the lock.

> 
> 	David.
> 
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