[RFC][PATCH] sunrpc: fix oops in rpc_create() when the mount namespace is unshared

[Cedric Le Goater]

Serge E. Hallyn wrote:
> Quoting Eric W. Biederman (ebiederm at xmission.com):
>> "Serge E. Hallyn" <serue at us.ibm.com> writes:
>>
>>> Thanks, Cedric.  Eric is probably right about the long-term fix, but
>>> yeah it might take a while to properly wade through the sunrpc and nfs
>>> layers to store the nodename at nfs mount time, and in the meantime this
>>> fixes a real oops.
>> A very esoteric oops that hasn't shown up for two years.
> 
> But an easily reproducible one.
> 
> It's not as though we'll stop looking for the right fix just bc we have
> this "bad" fix in for a short while.
> 
>> Please let's look at this and see what it would take to fix this
>> properly.
> 
> Of course.  Cedric is looking at the best way to fix it...

yes. well, my eyes are making progress in the NFS code. it will take some 
time :)

>> What are we trying to achieve by reading utsname?
> 
> It looks like it gets copied into the sunrpc messages so I assume it is
> a part of the sunrpc spec?
> 
> I don't want to do this, but we *could* put a conditional in utsname()
> to have it return init_utsname if current->nsproxy is null...

I nearly did that one but it will hide future misusage of utsname(). So 
I think it's better to keep it that way, and let the machine oops when
we need to fix our code. 

C.