CVE-2026-97905cpufreq: zero-initialize policy cpumask before sysfs publication

Official description

In the Linux kernel, the following vulnerability has been resolved: cpufreq: zero-initialize policy cpumask before sysfs publication cpufreq_policy_alloc() allocates policy->cpus with alloc_cpumask_var(), i.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus masks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate kmalloc_node() allocation, so its bitmap holds whatever the slab allocator left behind: cpufreq_online() cpufreq_policy_alloc() alloc_cpumask_var(&policy->cpus) /* bitmap is uninitialized */ kobject_init_and_add() /* policy%u/ appears in sysfs */ cpufreq_policy_online() cpumask_copy(policy->cpus, cpumask_of(cpu)) /* first valid value */ This leaves a window in which the sysfs attributes are already reachable while policy->cpus is still garbage. show()/store() gate on policy_is_inactive(), i.e. cpumask_empty(policy->cpus), so a non-zero bitmap makes them run the attribute callbacks on a policy that is not initialized yet. Fix this by using zalloc_cpumask_var() for policy->cpus.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e13370c5b549712f49f80234df249303381c53b4
• https://git.kernel.org/stable/c/e807920031ca32b668f9e7a1efbd21858f03d64b
• https://git.kernel.org/stable/c/ca52482508b3ac9febe74ca4f732647d394727b8
• https://git.kernel.org/stable/c/06f273d29e5e0fe5c775a65c563fbeed8cd94c7a
• https://git.kernel.org/stable/c/0de2f3918fbbbb767e7e716178194b66560dd12a
• https://git.kernel.org/stable/c/6e166b9281dec98aed19213a84235250e5fdb081
• https://git.kernel.org/stable/c/bbc0472d2270bf732142ca71579d6ede636174ed
• https://git.kernel.org/stable/c/54d37bcf2f497140b9207968557ddb484058e749