[LTP] [PATCH 2/2] nfsstat01: Check that RPC stats don't leak between net namespaces

[Martin Doucha]

On 30. 08. 24 20:10, Chuck Lever wrote:
> On Fri, Aug 30, 2024 at 04:13:40PM +0200, Martin Doucha wrote:
>> When the NFS server and client run on the same host in different net
>> namespaces, check that RPC calls from the client namespace don't
>> change RPC statistics in the root namespace.
>>
>> Signed-off-by: Martin Doucha <mdoucha@suse.cz>
>> ---
>>
>> I've initially tried to test both NFS and RPC client stats but it appears
>> that NFS client stats are still shared across all namespaces. Only RPC
>> client stats are separate for each net namespace. The kernel patchset[1]
>> which introduced per-NS stats confirms that only RPC stats have been changed.
> 
> I believe that is correct, Josef changed only RPC counters. Which
> counters did you expect also would be containerized, exactly?
> Perhaps this issue should be raised on linux-nfs@vger, it could be
> considered to be another information leak.

I tried to test the NFS client call counters, fields 13, 15 or 24 
(depending on NFS version) in the "procX" line of /proc/net/rpc/nfs. 
These are the counters that the test already checks after RPC.

Although when I think about it some more, I'm not sure whether the 
NFS/RPC client statistics should be attached to network namespaces in 
the first place. AFAICT, processes from any network namespace can 
trigger client calls for both RPC and NFS as long as they can access the 
NFS mountpoint. Perhaps a mount namespace would be the more logical 
domain for counting per-NS statistics instead?

-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic