CVE-2025-38539: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38539 affects the Linux kernel and involves a race condition in the trace event system. The vulnerability was discovered and disclosed on August 16, 2025. The issue occurs when modules with trace events are loaded simultaneously, potentially leading to list corruption and kernel crashes (NVD CVE).

The vulnerability stems from a synchronization issue in the Linux kernel's tracing subsystem. When a module is loaded, it adds trace events defined by the module and may need to modify the modules trace printk formats to replace enum names with their values. If two modules are loaded concurrently, the addition of events to the ftrace_events list can corrupt the list traversal during printk format string modifications (Debian Tracker).

The vulnerability can result in kernel crashes when multiple modules with trace events are loaded simultaneously. This occurs due to corruption in the ftrace_events list traversal, which can lead to system instability and potential denial of service (NVD CVE).

The fix involves adding proper synchronization using traceeventsem for write operations while adding new events. Additionally, a lockdepassertheld() check has been added on the semaphore in _traceaddeventdirs() during list iteration. The vulnerability has been fixed in various Linux distributions, including Debian bookworm (security) version 6.1.147-1 and Debian trixie (security) version 6.12.41-1 (Debian Tracker).