cpufreq: intel_pstate: Fix object lifecycle issue in update_qos_request()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: cpufreq: intel_pstate: Fix object lifecycle issue in update_qos_request() The cpufreq_cpu_put() call in update_qos_request() takes place too early because the latter subsequently calls freq_qos_update_request() that indirectly accesses the policy object in question through the QoS request object passed to it. Fortunately, update_qos_request() is called under intel_pstate_driver_lock, so this issue does not matter for changing the intel_pstate operation mode, but it theoretically can cause a crash to occur on CPU device hot removal (which currently can only happen in virt, but it is formally supported nevertheless). Address this issue by modifying update_qos_request() to drop the reference to the policy later.

References

• https://git.kernel.org/stable/c/15ac9579ebdaf22a37d7f60b3a8efc1029732ef9
• https://git.kernel.org/stable/c/bc26564bcc659beb6d977cd6eb394041ec2f2851
• https://git.kernel.org/stable/c/ad4e8f9bdbef11a19b7cb93e7f313bf59bdcc3b4
• https://git.kernel.org/stable/c/0a58d3e77b22b087a57831c87cafd360e144a5bd
• https://git.kernel.org/stable/c/69a18ff6c60e8e113420f15355fad862cb45d38e
• https://git.kernel.org/stable/c/ba63d4e9857a72a89e71a4eff9f2cc8c283e94c3
• https://git.kernel.org/stable/c/57e4a6aadf12578b96a038373cffd54b3a58b092
• https://git.kernel.org/stable/c/69e5d50fcf4093fb3f9f41c4f931f12c2ca8c467