CVE-2024-57951 hrtimers: Handle CPU state correctly on hotplug

In the Linux kernel, the following vulnerability has been resolved: hrtimers: Handle CPU state correctly on hotplug Consider a scenario where a CPU transitions from CPUHPONLINE to halfway through a CPU hotunplug down to CPUHPHRTIMERSPREPARE, and then back to CPUHPONLINE: Since hrtimerspreparecpu...