CVE-2026-64373

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

cpufreq: Fix hotplug-suspend race during reboot

During system reboot, cpufreq_suspend() is called via the kernel_restart() -> device_shutdown() path. Unlike the normal system suspend path, the reboot path does not call freeze_processes(), so userspace processes and kernel threads remain active.

This allows CPU hotplug operations to run concurrently with cpufreq_suspend(). The original code has no synchronization with CPU hotplug, leading to a race condition where governor_data can be freed by the hotplug path while cpufreq_suspend() is still accessing it, resulting in a null pointer dereference:

Unable to handle kernel NULL pointer dereference Call Trace: do_kernel_fault+0x28/0x3c cpufreq_suspend+0xdc/0x160 device_shutdown+0x18/0x200 kernel_restart+0x40/0x80 arm64_sys_reboot+0x1b0/0x200

Fix this by adding cpus_read_lock()/cpus_read_unlock() to cpufreq_suspend() to block CPU hotplug operations while suspend is in progress.

[ rjw: Changelog edits ]

Affected Software

References

• https://git.kernel.org/stable/c/6d5dd354c37abaf4d60400c55c71f23ba2b33639
• https://git.kernel.org/stable/c/6e175c00c62dca3d91b987015808b5d52e8db2b4
• https://git.kernel.org/stable/c/73255d702c7560185fd5951aadcf7eb057c2f453
• https://git.kernel.org/stable/c/9103078c7b3091a2fbb52af176f95982ee7dd7f8
• https://git.kernel.org/stable/c/a0106b41f9a724868d390b8b3b4ea5ca0e04ea53
• https://git.kernel.org/stable/c/a0ef2fc89d28ca62923376c4b8ffaa57136a36be
• https://git.kernel.org/stable/c/a9029dd55696c651ee46912afa2a166fa456bb3e
• https://git.kernel.org/stable/c/cd4524ff6567fa4458a5bec4b017105e671d393e