CVE-2026-23332

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

cpufreq: intel_pstate: Fix crash during turbo disable

When the system is booted with kernel command line argument "nosmt" or "maxcpus" to limit the number of CPUs, disabling turbo via:

echo 1 > /sys/devices/system/cpu/intelpstate/noturbo

results in a crash:

PF: supervisor read access in kernel mode PF: errorcode(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI ... RIP: 0010:storeno_turbo+0x100/0x1f0 ...

This occurs because foreachpossiblecpu() returns CPUs even if they are not online. For those CPUs, allcpudata[] will be NULL. Since commit 973207ae3d7c ("cpufreq: intelpstate: Rearrange max frequency updates handling code"), allcpudata[] is dereferenced even for CPUs which are not online, causing the NULL pointer dereference.

To fix that, pass CPU number to intelpstateupdatemaxfreq() and use allcpudata[] for those CPUs for which there is a valid cpufreq policy.