CVE-2021-47416 Affecting kernel-rt-kvm package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-rt-kvm package and not the kernel-rt-kvm package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

phy: mdio: fix memory leak

Syzbot reported memory leak in MDIO bus interface, the problem was in wrong state logic.

MDIOBUS_ALLOCATED indicates 2 states: 1. Bus is only allocated 2. Bus allocated and __mdiobus_register() fails, but device_register() was called

In case of device_register() has been called we should call put_device() to correctly free the memory allocated for this device, but mdiobus_free() calls just kfree(dev) in case of MDIOBUS_ALLOCATED state

To avoid this behaviour we need to set bus->state to MDIOBUS_UNREGISTERED before calling device_register(), because put_device() should be called even in case of device_register() failure.

• https://access.redhat.com/security/cve/CVE-2021-47416
• https://git.kernel.org/stable/c/064c2616234a7394867c924b5c1303974f3a4f4d
• https://git.kernel.org/stable/c/0d2dd40a7be61b89a7c99dae8ee96389d27b413a
• https://git.kernel.org/stable/c/2250392d930bd0d989f24d355d6355b0150256e7
• https://git.kernel.org/stable/c/2397b9e118721292429fea8807a698e71b94795f
• https://git.kernel.org/stable/c/25e9f88c7e3cc35f5e3d3db199660d28a15df639
• https://git.kernel.org/stable/c/414bb4ead1362ef2c8592db723c017258f213988
• https://git.kernel.org/stable/c/ca6e11c337daf7925ff8a2aac8e84490a8691905
• https://git.kernel.org/stable/c/f4f502a04ee1e543825af78f47eb7785015cd9f6