CVE-2025-68329: tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix WARNON in tracingbuffersmmapclose for split VMAs
When a VMA is split (e.g., by partial munmap or MAPFIXED), the kernel calls vmops->close on each portion. For trace buffer mappings, this results in ringbufferunmap() being called multiple times while ringbuffermap() was only called once.
This causes ringbufferunmap() to return -ENODEV on subsequent calls because usermapped is already 0, triggering a WARNON.
Trace buffer mappings cannot support partial mappings because the ring buffer structure requires the complete buffer including the meta page.
Fix this by adding a maysplit callback that returns -EINVAL to prevent VMA splits entirely.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Add a may_split callback for trace buffer mappings that returns -EINVAL to prevent VMA splitting.
Linux kernel tracing ring buffer trace buffer mappings may_split callback = -EINVAL
Event History
Frequently Asked Questions
What is the severity of CVE-2025-68329?
CVE-2025-68329 is considered a moderate severity vulnerability due to its impact on trace buffer mappings in the Linux kernel.
How do I fix CVE-2025-68329?
To fix CVE-2025-68329, you should update to the latest stable version of the Linux kernel that addresses this vulnerability.
What systems are affected by CVE-2025-68329?
CVE-2025-68329 affects systems running the impacted versions of the Linux kernel that utilize tracing buffer mappings.
What are the potential consequences of exploiting CVE-2025-68329?
Exploiting CVE-2025-68329 may lead to system instability or crashes due to improper handling of Virtual Memory Areas.
Is CVE-2025-68329 related to any specific kernel versions?
CVE-2025-68329 affects specific versions of the Linux kernel that allow for potentially unsafe memory operations.