drm/imagination: Fix kernel crash when hard resetting the GPU

Overview

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

drm/imagination: Fix kernel crash when hard resetting the GPU

The GPU hard reset sequence calls pm_runtime_force_suspend() and pm_runtime_force_resume(), which according to their documentation should only be used during system-wide PM transitions to sleep states.

The main issue though is that depending on some internal runtime PM state as seen by pm_runtime_force_suspend() (whether the usage count is <= 1), pm_runtime_force_resume() might not resume the device unless needed. If that happens, the runtime PM resume callback pvr_power_device_resume() is not called, the GPU clocks are not re-enabled, and the kernel crashes on the next attempt to access GPU registers as part of the power-on sequence.

Replace calls to pm_runtime_force_suspend() and pm_runtime_force_resume() with direct calls to the driver's runtime PM callbacks, pvr_power_device_suspend() and pvr_power_device_resume(), to ensure clocks are re-enabled and avoid the kernel crash.

Affected

• Linux >= cc1aeedb98ad347c06ff59e991b2f94dfb4c565d < 9f852d301f642223c4798f3c13ba15e91165d078
• Linux >= cc1aeedb98ad347c06ff59e991b2f94dfb4c565d < e066cc6e0f094ca2120f1928d126d56f686cd73e
• Linux >= cc1aeedb98ad347c06ff59e991b2f94dfb4c565d < d38376b3ee48d073c64e75e150510d7e6b4b04f7
• Linux 6.8

Remediation

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