[Users] /dev/.../umad permissions

[Ira Weiny]

On Wed, 27 Feb 2013 18:37:24 -0600
John Valdes <valdes at anl.gov> wrote:

> On Wed, Feb 27, 2013 at 04:14:46PM -0800, Ira Weiny wrote:
> > On Wed, 27 Feb 2013 17:30:55 -0600 John Valdes <valdes at anl.gov> wrote:
> > > 
> > > I'd like to have a non-root user be able to query
> > > port stats [...]
> > > making umad non-root readable would be the simplest approach, I'm
> > > curious to know the security implications before actually making it
> > > so.
> > 
> > The problem with this approach is that perfquery, ibqueryerrors must also write to the umad device to send the Get() MAD's.  This is true with most of the diags out there.
> 
> Oh right, of course; to read data from a network, you need to send out
> a read request, which requires write access to the network (umad)
> device.  OK, I guess I go with option 2 or 3.
> 
> > Another option would be to look into the performance manager within OpenSM.  With a lot of luck it will soon be able to query PortCountersExtended and be able to give accurate data counters!  :-D
> 
> Or option 4. ;)
> 
> It's too bad the extended port counters aren't exposed under /sys (eg,
> in /sys/class/infiniband/mlx4_0/ports/1/counters), as those are
> directly readable by anyone and don't require any network
> communication to read.

Actually, are you sure those counters are not 64bits wide?  The driver may be exporting the 64bit versions.  But I am not sure.

Ira

> 
> John
> 
> ----------------------------------------------------------------------
> John Valdes                  Mathematics and Computer Science Division
> valdes at anl.gov                             Argonne National Laboratory


-- 
Ira Weiny
Member of Technical Staff
Lawrence Livermore National Lab
925-423-8008
weiny2 at llnl.gov