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.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
No advisories yet.
Fri, 25 Sep 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-457 |
Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | cpufreq: zero-initialize policy cpumask before sysfs publication | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:22:31.046Z
Reserved: 2026-09-25T10:18:58.200Z
Link: CVE-2026-97905
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:17.403
Modified: 2026-09-25T11:17:17.403
Link: CVE-2026-97905
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-09-25T14:30:14Z