net: arc_emac: Fix use after free in arc_mdio_probe()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: arc_emac: Fix use after free in arc_mdio_probe() If bus->state is equal to MDIOBUS_ALLOCATED, mdiobus_free(bus) will free the "bus". But bus->name is still used in the next line, which will lead to a use after free. We can fix it by putting the name in a local variable and make the bus->name point to the rodata section "name",then use the name in the error message without referring to bus to avoid the uaf.

References

• https://git.kernel.org/stable/c/84c831803785c2c3bec5c28c0e8a0b72f6b41d4d
• https://git.kernel.org/stable/c/bc0e610a6eb0d46e4123fafdbe5e6141d9fff3be