Re: [PATCH] RDMA/core: fix a NULL-pointer dereference in hw_stat_device_show()

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Feb 21, 2025 at 04:34:25AM +0000, Parav Pandit wrote:

> I just tried reproducing now on 6.12+ kernel manually.
> It appears impossible to reach flow to me as intended in the commit
> I listed.

It looks to me like this:

static void rdma_init_coredev(struct ib_core_device *coredev,
			      struct ib_device *dev, struct net *net)
{
	coredev->dev.groups = dev->groups;
                   ^^^^^^^^^^^^^^^^^^^^^

Copies the sysfs groups from the normal ib_dev which includes the hw_*
stuff to the per-NS device?

Everything in that groups list must use rdma_device_to_ibdev()

int ib_setup_device_attrs(struct ib_device *ibdev)
{
[..]
		attr->attr.show = hw_stat_device_show;
		attr->show = show_hw_stats;
		data->group.attrs[pos] = &attr->attr.attr;
[..]
			ibdev->groups[i] = &data->group;

Which means the sysfs reported here is in that list?

Maybe this was misses when the sysfs was shut off?

Jason