Re: [PATCH net] net: dsa: sja1105: fix use-after-free after calling of_find_compatible_node, or worse

On Fri, Aug 20, 2021 at 10:54 AM Andrew Lunn [off-list ref] wrote:

quoted

3. If dsa_register_switch() fails, we can't defer the probe (because
it already succeeded). But I'm not sure if it's a likely error code.

That is not a safe assumption. The tagging driver can be a module, and

I don't know what "tagging driver" means. And yes, this is just a test
patch for now.

not be loaded yet. So we defer probing to allow it to load.

Ethernet switches can be a big graph of parts, not a nice tree of
parts.

fw_devlink can handle graphs well. It has cycle detection for a reason
:) Look at slide 10 for a complicated example:
https://linuxplumbersconf.org/event/7/contributions/787/attachments/529/942/LPC_2020_-_fw_devlink.pdf

However, after sending that email I realized that fw_devlink=on would
make sure all the dependencies of this device would have probed first
before it allows this to probe. So EPROBE_DEFER can't really happen.
But for now I just want to see if it fixes the issue Alvin was seeing.

-Saravana