Re: [PULL 2/2] vhost: replace rcu with mutex

From: Vlad Yasevich
Date: Tue Jun 03 2014 - 09:35:26 EST


On 06/03/2014 08:48 AM, Paolo Bonzini wrote:
> Il 02/06/2014 23:58, Eric Dumazet ha scritto:
>> This looks dubious
>>
>> What about using kfree_rcu() instead ?
>
> It would lead to unbound allocation from userspace.
>
>> translate_desc() still uses rcu_read_lock(), its not clear if the mutex
>> is really held.
>
> Yes, vhost_get_vq_desc must be called with the vq mutex held.
>
> The rcu_read_lock/unlock in translate_desc is unnecessary.
>

If that's true, then does dev->memory really needs to be rcu protected?
It appears to always be read under mutex.

-vlad

> Paolo
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/