Re: [PATCH 148/196] Infiniband: make ipath driver use default driver groups.

Greg KH
2008-01-25T22:25:24Z

On Fri, Jan 25, 2008 at 02:11:14PM -0800, Roland Dreier wrote:
> So I think it is coming from the following code in ipath_sysfs.c:
>
> int ipath_device_create_group(struct device *dev, struct ipath_devdata *dd)
> {
> int ret;
>
> ret = sysfs_create_group(&dev->kobj, &dev_attr_group);
> if (ret)
> goto bail;
>
> ret = sysfs_create_group(&dev->kobj, &dev_counter_attr_group);
> if (ret)
> goto bail_attrs;
>
> sysfs_remove_group(&dev->kobj, &dev_counter_attr_group);
> bail_attrs:
> sysfs_remove_group(&dev->kobj, &dev_attr_group);
> bail:
> return ret;
> }
>
> note that the success path falls through into the error path and
> removes the groups it just created, which means that on initialization
> the groups are already removed, so we hit the BUG on the second try to
> remove the groups on module exit.
>
> And I think this chunk of your patch:
>
> - snprintf(unit, sizeof(unit), "%02d", dd->ipath_unit);
> - ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, unit);
> - if (ret == 0)
> - goto bail;
> -
>
> was what broke it. (Note the "if (ret == 0) then skip error
> unwinding" code that got deleted by mistake -- not surprising given
> how hard to read that construction is)
>
> My bad for not testing -mm better. I'll queue this up to fix it:

Thanks for the fix, and sorry for causing that, it was a complex error
path :)

Although a BUG() for when we try to remove a file that is no longer
there seems pretty harsh, I think I'll change that to a WARN_ON() so
that people just know to fix up their code, not kill the kernel
entirely.

thanks,

greg k-h