CVE-2022-48848: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-48848 affects the Linux kernel's tracing/osnoise functionality. The vulnerability was discovered when using trace-cmd with specific parameters, which resulted in an attempt to unregister an already unregistered tracepoint. This occurs when trace-cmd first stops tracing and then switches the tracer to nop, equivalent to executing a sequence of commands in /sys/kernel/tracing/ (Kernel Git).

The issue manifests when the osnoise tracer stops the workload when no trace instance is actively collecting data, which can happen either by disabling tracing or disabling the tracer itself. The vulnerability was introduced in commit 2fac8d6486d5 ('tracing/osnoise: Allow multiple instances of the same tracer'). When triggered, it generates a kernel warning at kernel/tracepoint.c:404 in the tracepoint_probe_unregister function (Kernel Git).

When triggered, this vulnerability results in a kernel warning and attempted double unregistration of tracepoints. While this doesn't lead to system compromise, it can affect system stability and debugging capabilities (Kernel Git).

The vulnerability can be triggered through normal system operation using trace-cmd with specific parameters (trace-cmd record -e all -M 10 -p osnoise --poll) or by executing a sequence of commands in the tracing filesystem (Kernel Git).

The issue was fixed by using the existing trace_osnoise_callback_enabled variable to check if the events and workload are actually active before attempting to deactivate them. The fix was implemented in the Linux kernel through a patch that prevents double unregistration of events (Kernel Git).