segv_handler(9)

💅 segv_handler(9) — Kernel API Manual 💅

okay so bestie, this is the Kernel API Manual page for segv_handler(9), and we're talking about the SIGSEGV handler — like, the moment your kernel catches that segfault energy. no cap, it's giving “trap.c main character” and we're gonna walk through it together. 🫶

🎀 NAME 🎀

segv_handler — the SIGSEGV handler. periodt. 💥

✨ SYNOPSIS ✨

void segv_handler (int sig , struct siginfo *unused_si , struct
       uml_pt_regs *regs , void *mc );

🌸 ARGUMENTS 🌸

• sig — the signal number. that's the whole point, bestie.
• unused_si — the signal info struct; it's literally unused in this handler, so don't come for it. 🙈
• regs — the ptrace register information. iconic data source. ✨
• mc — the mcontext of the signal. we love a context king. 👑

🦋 DESCRIPTION 🦋

okay so the handler first extracts faultinfo from the UML ptrace regs struct. that's step one, no skipping. 💅

then there's a vibe check: if the userfault did not happen in an UML userspace process, bad_segv is called. yes, bad_segv — that's the name, not me being dramatic. 😭

otherwise? the signal did happen in a cloned userspace process, and the handler handles it. slay. ✅

🔍 SEE ALSO 🔍

• Kernel file ./arch/um/kernel/trap.c — go read it, iykyk. 📖

with so much love and zero segfaults (jk, that's the point), your kernel bestie 💖 — source/version: ./arch/um/kernel; date: October 2026. segv_handler(9) out. 🎀