Re: [PATCH] driver core: ensure a device has valid node id in device_add()

From: Michal Hocko
Date: Wed Sep 11 2019 - 03:34:55 EST

On Wed 11-09-19 15:22:30, Yunsheng Lin wrote:
> It seems that there is no protection that prevent setting the node
> of device to an invalid node.
> And the kernel does have a few different check now:
> 1) some does " < 0" check;
> 2) some does "== NUMA_NO_NODE" check;
> 3) some does ">= MAX_NUMNODES" check;
> 4) some does "< 0 || >= MAX_NUMNODES || !node_online(node)" check.
> We need to be consistent about the checking, right?

You can try and chase each of them and see what to do with them. I
suspect they are a result of random attempts to fortify the code in many
cases. Consistency is certainly good but spreading more checks all over
the place just adds more cargo cult. Each check should be reasonably

Michal Hocko