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SubjectRe: netlink: Add barrier to netlink_connect for theoretical case
Hello, Herbert.

On Fri, Sep 25, 2015 at 09:43:27AM +0800, Herbert Xu wrote:
> Well had you said this in the first place I would've fixed it a
> long time ago. There aren't any in-kernel users right now and
> even if there were they'd have to do a connect/bind/sendmsg on
> the same socket in two threads at the same time. But let's close
> this theoretical hole:

I'm not even sure we guarantee memory barrier on kernel/user
crossings. In practice, we probably have enough barriers (e.g. some
syscall traps imply barrier) but I can't think of a reason why we'd
guarantee the existence of barrier there. As an extreme example,
imagine UML on an architecture with relaxed memory model.

Thanks.

--
tejun


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