CVE-2024-46845: tracing/timerlat: Only clear timer if a kthread exists

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-09-27 · updated 2026-08-04
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: tracing/timerlat: Only clear timer if a kthread exists The timerlat tracer can use user space threads to check for osnoise and timer latency. If the program using this is killed via a SIGTERM, the threads are shutdown one at a time and another tracing instance can start up resetting the threads before they are fully closed. That causes the hrtimer assigned to the kthread to be shutdown and freed twice when the dying thread finally closes the file descriptors, causing a use-after-free bug. Only cancel the hrtimer if the associated thread is still around. Also add the interface_lock around the resetting of the tlat_var->kthread. Note, this is just a quick fix that can be backported to stable. A real fix is to have a better synchronization between the shutdown of old threads and the starting of new ones.

Affected products

Linux kernel: from 6.5 before 6.6.51; from 6.7 before 6.10.10; 6.11-rc1, 6.11-rc2, 6.11-rc3, 6.11-rc4, 6.11-rc5, 6.11-rc6 — fixed in 6.10.10, 6.6.51

How to fix

Upgrade to a fixed version: Linux kernel 6.10.10, 6.6.51. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2024-46845 or the next vulnerability affects your stack