CVE-2023-53612

A NULL pointer dereference flaw was found in the Linux kernel's coretemp hardware monitoring driver in the platform device handling logic. A local privileged user who disables drivers_autoprobe for the platform bus can trigger this issue by initiating CPU hotplug operations, causing the driver to assume synchronous device binding when it does not occur. This results in a NULL pointer dereference leading to denial of service through a kernel crash or deadlock during suspend operations.

The coretemp driver uses an unconventional architecture where platform devices are dynamically created and destroyed from CPU hotplug notifiers. The code assumes that platform_device_add() will synchronously bind the driver and set drvdata before returning, but this assumption breaks when drivers_autoprobe is disabled for the platform bus. When hotplug events occur under these conditions, the driver dereferences uninitialized drvdata, causing a NULL pointer dereference. Additionally, the approach of managing platform devices from hotplug notifiers creates deadlock potential during system suspend and lockdep issues when other subsystems register CPU hotplug notifiers from platform bus notifiers.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.