System call instrumentation on Linux/x86‑64 using memory‑indirect calls, part I

Rambles around computer science Diverting trains of thought, wasting precious time 15 06 2026--> Mon, 15 Jun 2026 System call instrumentation on Linux/x86-64 using memory-indirect calls (in vain?), part one My libsystrap library provides a simple instrumentation of system calls in Linux x86-64 userland. However, its current implementation suffers a double-trap overhead: system calls become ud2, which generates a SIGILL trap. Then we run the system call itself from within the signal handler, caus