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CVE-2025-40327
Linux Kernel perf async-profiler CPU Clock Hang Vulnerability
Description

In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix system hang caused by cpu-clock usage cpu-clock usage by the async-profiler tool can trigger a system hang, which got bisected back to the following commit by Octavia Togami: 18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage") causes this issue The root cause of the hang is that cpu-clock is a special type of SW event which relies on hrtimers. The __perf_event_overflow() callback is invoked from the hrtimer handler for cpu-clock events, and __perf_event_overflow() tries to call cpu_clock_event_stop() to stop the event, which calls htimer_cancel() to cancel the hrtimer. But that's a recursion into the hrtimer code from a hrtimer handler, which (unsurprisingly) deadlocks. To fix this bug, use hrtimer_try_to_cancel() instead, and set the PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer() to stop the event once it sees the PERF_HES_STOPPED flag. [ mingo: Fixed the comments and improved the changelog. ]

INFO

Published Date :

Dec. 9, 2025, 6:28 a.m.

Last Modified :

Dec. 9, 2025, 6:28 a.m.

Remotely Exploit :

No

Source :

None
Affected Products

The following products are affected by CVE-2025-40327 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Resolve system hangs caused by CPU-clock usage in perf by using hrtimer_try_to_cancel.
  • Update the Linux kernel to the resolved version.
  • Use hrtimer_try_to_cancel instead of htimer_cancel.
  • Set the PERF_HES_STOPPED flag.
  • Stop the event when PERF_HES_STOPPED flag is seen.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-40327.

URL Resource
https://git.kernel.org/stable/c/6b8c512811644cf2f5eaf6f44e928683c54127f0
https://git.kernel.org/stable/c/eb3182ef0405ff2f6668fd3e5ff9883f60ce8801
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-40327 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-40327 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-40327 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
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