CVE-2022-48848 is a vulnerability identified in the Linux kernel's tracing subsystem, specifically within the osnoise tracer component. The issue arises from an improper handling of tracepoint unregistration, where the kernel attempts to unregister tracepoint events twice. This double unregistration leads to kernel warnings and potentially unstable kernel behavior. The vulnerability was reported when using the trace-cmd tool with the osnoise tracer, which caused a kernel warning related to tracepoint_probe_unregister. The root cause is that the osnoise tracer stops its workload when no trace instance is actively collecting data, such as when tracing is disabled or the tracer is switched off. However, the code did not properly check if the events were already unregistered before attempting to unregister them again. The fix involves using the existing trace_osnoise_callback_enabled variable to verify whether the events and workload are active before deactivating them, preventing the double unregistration. This vulnerability affects Linux kernel versions around 5.17.0-rc6-next-20220307-nico+ and potentially others with similar tracing implementations. While the vulnerability triggers kernel warnings, it does not appear to directly allow code execution or privilege escalation, and no known exploits are reported in the wild as of the publication date. The issue is primarily a stability and reliability concern within the kernel tracing infrastructure.

For European organizations relying on Linux-based systems, especially those using kernel tracing tools like trace-cmd for performance monitoring or debugging, this vulnerability could lead to kernel instability or unexpected warnings. While it does not directly compromise confidentiality or integrity, the resulting kernel warnings and potential instability could disrupt critical services, particularly in environments where kernel tracing is actively used for diagnostics or performance tuning. Systems running customized or development kernel versions with the affected tracing code are more susceptible. Disruptions in kernel tracing might delay incident response or system diagnostics, indirectly impacting operational continuity. However, since no known exploits exist and the vulnerability requires specific tracing operations, the immediate risk to most production systems is limited. Nonetheless, organizations with high-dependability Linux systems, such as cloud providers, telecommunications infrastructure, or industrial control systems, should consider the impact on system reliability and monitoring capabilities.

To mitigate this vulnerability, organizations should apply the official Linux kernel patches that address the double unregistration issue in the osnoise tracer. If using trace-cmd or similar tracing tools, ensure they are updated to versions compatible with the patched kernel. Avoid running tracing commands that trigger the vulnerability until patches are applied. For environments where kernel tracing is critical, implement monitoring to detect kernel warnings related to tracepoint unregistration. Additionally, consider restricting tracing operations to trusted administrators to reduce accidental triggering. For custom or embedded Linux distributions, coordinate with vendors or maintainers to integrate the fix promptly. Testing kernel updates in staging environments before production deployment is recommended to verify stability. Finally, maintain regular kernel updates as part of the security hygiene to prevent exposure to known kernel vulnerabilities.