drm/amdgpu: fix ACP MFD device leak on init failure

Overview

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

drm/amdgpu: fix ACP MFD device leak on init failure

acp_hw_init() registers ACP child devices with mfd_add_devices() before attaching them to the ACP power domain and initializing the hardware.

If attaching a child to the power domain fails, or if the ACP reset or clock enable operation times out, the failure path frees only the source cell, resource, and platform-data allocations. The child platform devices already registered by mfd_add_devices() remain registered and are never released.

Remove the children from the power domain and unregister the MFD devices on failures that occur after mfd_add_devices() succeeds. Keep mfd_add_devices() failures on the existing cleanup path since the MFD core already rolls back partially registered children itself.

The issue was identified by a static analysis tool I developed and confirmed by manual review.

(cherry picked from commit 63da68d6a2279ec945581c990c5a59a5ae8b5560)

Affected

• Linux >= 25030321ba2860c56651429a4f28d94a6483d952 < 2b9a53940a2bc063ea4cd09ee49220a503a0170c
• Linux >= 25030321ba2860c56651429a4f28d94a6483d952 < 587469076e4ffb617f7ad1a0c4a13072a3e87113
• Linux >= 25030321ba2860c56651429a4f28d94a6483d952 < abf854513bc19e6e24d45353ac99ec5627ee0acc
• Linux >= 25030321ba2860c56651429a4f28d94a6483d952 < f0013046151b7467e62c471c1c83d63ea255799c
• Linux 4.6

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.