Segmentation Fault in Linux Kernel due to PEBS-via-PT with Sample Frequency
Summary
DEBIAN-CVE-2025-38055: In the Linux kernel, the following vulnerability has been resolved: perf/x86/intel: Fix segfault with PEBS-via-PT with sample_freq Currently, using PEBS-via-PT with a sample frequency instead of a sample period, causes a... Affects linux versions < 6.12.32-1. Fixed in 6.12.32-1. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, responsible for managing hardware resources and providing essential services to applications. It is known for its stability, performance, and flexibility. However, vulnerabilities can arise, impacting system reliability and security. The specific issue at hand involves the Performance Event-Based Sampling (PEBS) feature, which is used for performance monitoring. This vulnerability can lead to segmentation faults when certain configurations are used, potentially causing system crashes or instability.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the handling of Performance Event-Based Sampling (PEBS) via Processor Trace (PT) when a sample frequency is used instead of a sample period. This issue arises because the function intel_pmu_pebs_event_update_no_drain() incorrectly assumes that all enabled PEBS bits represent counter indexes, which is not always true. When bits 60 and 61 are set for PEBS-via-PT purposes, it can lead to a NULL pointer dereference, resulting in a segmentation fault. This vulnerability can cause system crashes and may affect the reliability of performance monitoring tools.
How To Fix
Minimum fixed version
6.12.32-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. However, users can avoid using PEBS-via-PT with a sample frequency until the system is updated to the patched version.
Conclusion
The vulnerability identified in the Linux kernel regarding PEBS-via-PT with sample frequency poses significant risks to system stability and performance monitoring. Users are advised to update their systems to the patched version to mitigate these risks. Regular updates and monitoring for vulnerabilities are crucial for maintaining system integrity.
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FAQ
PEBS-via-PT is a feature in the Linux kernel that allows for performance monitoring using Processor Trace. It helps in capturing detailed performance data.
The vulnerability can lead to segmentation faults, causing system crashes and instability, particularly when using specific performance monitoring configurations.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
While the primary risk is system instability and crashes, there is a potential for data loss if the system crashes during critical operations.
It is recommended to regularly check for updates and apply them promptly to ensure that your system is secure and stable.
References
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