In the Linux kernel, the following vulnerability has been resolved:
net: dsa: mv88e6xxx: Correct check for empty list
Since commit a3c53be55c95 ("net: dsa: mv88e6xxx: Support multiple MDIO busses") mv88e6xxxdefaultmdiobus() has checked that the return value of listfirst_entry() is non-NULL.
This appears to be intended to guard against the list chip->mdios being empty. However, it is not the correct check as the implementation of listfirstentry is not designed to return NULL for empty lists.
Instead, use listfirstentryornull() which does return NULL if the list is empty.
Flagged by Smatch. Compile tested only.