Bug 2507271 (CVE-2026-64373)

Summary: CVE-2026-64373 kernel: cpufreq: Fix hotplug-suspend race during reboot
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's CPU frequency scaling (cpufreq) subsystem. During a system reboot, a race condition can occur when the system attempts to suspend CPU frequency operations while CPU hotplug operations are still active. This can lead to a null pointer dereference, which may cause the system to crash, resulting in a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-07-25 10:13:52 UTC 
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 ]
Comment 1 TEJ RATHI 2026-07-27 06:23:06 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072523-CVE-2026-64373-2ee3@gregkh/T