title: Watch a Kernel Symbol Using Breakpoint Hardware
name: hw_watch_sym.stp
version: 1.0
author: William Cohen
keywords: memory watchpoint
subsystem: memory
status: production
exit: user-controlled
output: trace
scope: system-wide
description: The script will watch accesses to the starting address of a single kernel symbol and prints a traceback each time the symbol is accessed. This script needs to be run as root to allow access to the breakpoint hardware.
test_support: perf stat -a --event=mem:0x`grep "vm_dirty_ratio" /proc/kallsyms | awk '{print $1}'` /bin/true
test_check: stap --all-modules -p4 hw_watch_sym.stp vm_dirty_ratio
test_installcheck: stap --all-modules hw_watch_sym.stp vm_dirty_ratio -T 5