Re: [ndctl PATCH v3 00/10] daxctl: add a new reconfigure-device command

["Verma, Vishal L" <vishal.l.verma@intel.com>]

On Fri, 2019-05-17 at 13:41 -0400, Pavel Tatashin wrote:
> > Hi Pavel,
> > 
> > I've still not been able to hit this in my testing, is it something
> > you
> > hit only after applying these patches? i.e. does plain v65 work?
> 
> Yes, plain v65 works, but with these patches I see this error.
> 
Hm, So there are only two patches that touch the add_dax_dev function:

  2bf9a8e libdaxctl: add interfaces to enable/disable devices
  25be8f4 libdaxctl: add interfaces to get/set the online state for a node

And of these, the second one to get the target node doesn't return an
error in any case.

The first one can fail, so it must be that condition you're hitting, but
I'm not sure in what way it is failing.

The exact check is:

	sprintf(path, "%s/modalias", daxdev_base);
	rc = sysfs_read_attr(ctx, path, buf);
	/* older kernels may be lack the modalias attribute */
	if (rc < 0 && rc != -ENOENT)
		goto err_read;
	if (rc == 0) {
		dev->kmod_list = to_module_list(ctx, buf);
		if (dev->kmod_list == NULL)
			goto err_read;
	} else
		dbg(ctx, "%s: modalias attribute missing\n", devname);

Do you have the file:

  /sys/bus/dax/devices/dax0.0/modalias

And what does it contain? On my system:

  $ cat /sys/bus/dax/devices/dax0.0/modalias 
  dax:t0

If this is missing, it would seem you're not correctly in 'dax-bus'
mode, but that is kind of required for the kmem functionality anyway, so
I'm not sure where we might be tripping.
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm