CVE-2025-38017

/// Technical 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 su

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References