How does eBPF enable low-overhead system tracing in Linux environments?

Extended Berkeley Packet Filter (eBPF) fundamentally changes how operators gain system-level insights into Linux kernels. Instead of modifying kernel code or compiling custom kernel modules, eBPF runs sandboxed programs directly inside the operating system core.

Safe Kernel-Level Tracing

Because an in-kernel verifier validates every eBPF program before loading, system instrumentation runs safely without risking crash loops or kernel panics.

Writing a Simple System Call Probe in C

The following C snippet hooks directly into kernel-level tracing points to monitor execve system calls as processes launch:

// Include vmlinux header defining kernel internal structures
#include 
#include 

// Attach eBPF function to the sys_enter_execve tracepoint
SEC("tracepoint/syscalls/sys_enter_execve")
int trace_execve_entry(struct trace_event_raw_sys_enter *ctx) {
    u32 pid = bpf_get_current_pid_tgid() >> 32;
    char comm[16];
    
    // Safely retrieve the executable name running current process
    bpf_get_current_comm(&comm, sizeof(comm));
    
    // Output kernel log message readable via trace_pipe
    bpf_printk("Process spawned: PID %d, Name: %s\n", pid, comm);
    return 0;
}

// Declare GPL license compatibility required by kernel helper routines
char _license[] SEC("license") = "GPL";

Through eBPF tracepoints, observability platforms track networking, security, and performance metrics with microsecond accuracy and minimal runtime overhead.