R's Workshop
Use HW breakpoint to Watch Kernel Data Address
因為 kerenl 的 tasklet 可以 access 任意的記憶體位置, 要如何在茫茫 tasklets 中找到是誰修改了某個變數在 debug 上非常重要. 還好 Linux kernel 提供了 HW breakpoint 的方式, 讓我們可以在要 monitor 的位置上註冊一個 trap. 當 kernel 對該位置讀寫時觸發 trap 來做進一步 debug, 比方說 dump stack.
Reference
- data_breakpoint.c - Sample HW Breakpoint file to watch kernel data address
- Hardware breakpoints in the Linux kernel through perf_events
- Watch a variable (memory address) change in Linux kernel, and print stack trace when it changes?
- Linux kernel hardware break points
- register_wide_hw_breakpoint continually triggers handler callback
- Linux 监测内存访问的方法汇总
Linux driver
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