Linux Kernel ACPI PRM Runtime Workqueue Initialization Vulnerability

A vulnerability in the Linux kernel's handling of ACPI PRM calls can lead to NULL pointer dereferences. This issue arises because PRM accesses may occur before the EFI subsystem is fully initialized, specifically before the workqueue required to handle these calls is allocated. The problem is related to the order of initialization calls, which can be sensitive to dependencies. As a result, the vulnerability affects the Linux kernel's EFI runtime services, particularly in the context of ACPI PRM handling.

Impact

The vulnerability can cause NULL pointer dereferences, potentially leading to system crashes or instability.

Reproduction

The vulnerability can be reproduced by triggering early ACPI PRM accesses before the EFI subsystem has fully initialized and allocated the necessary workqueue. This can occur due to the timing of initialization calls, which may not properly account for the dependencies of the ACPI PRM handling on the EFI runtime services.

Remediation

The vulnerability has been addressed by modifying the initialization process to allocate the required workqueue before any ACPI PRM accesses occur. Users should upgrade to the latest version of the Linux kernel where this fix has been applied.