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

On Wed, Aug 18, 2021 at 01:31:01AM +0300, Vladimir Oltean wrote:

So it's a circular dependency? Switch cannot finish probing because it
cannot connect to PHY, which cannot probe because switch has not
finished probing, which....

The missing piece of the puzzle might be that MAC drivers can either
connect to the PHY at probe time, or at .ndo_open time. DSA chooses to
call phylink_of_phy_connect() inside dsa_port_phylink_register(), so at
probe time. Maybe this is a reason why it is a problem for some drivers
but not for others.