Hi, This is the 3rd version of the series. I just updated 4/8 according to Ingo's comment.
This series tries to make kprobes instruction buffers read-only pages. Since those buffers are used for trampoline code, those are a part of "text area" and it should be marked as ro for avoiding unexpected modification. And this actually fix a warning rodata sanity check reported by lkp-robot. https://lkml.org/lkml/2017/2/27/161 This change requires changing the kprobe-booster at first because it can modify the instruction buffer to add a jump while resuming from single-stepping. Of course after we make the buffer readonly, we may not be able to modify it while probing. So, at first this series checks the current bootable instructions and fixes a missed instruction (call far), modifies can_boost to use x86 instruction decoder, and inserts "booster" jump while preparing instruction buffer instead of resuming from single-stepping. At last, it makes the buffers for kprobes and optprobe readonly. This series also has some cleanup patches related to above changes. Changes from V2: - [4/8]: Fix imbalanced curly braces and remove unneeded (void *) cast. --- Masami Hiramatsu (8): kprobes/x86: Fix not to boost call far instruction kprobes/x86: Fix the description of __copy_instruction() kprobes/x86: Use instruction decoder for booster kprobes/x86: Do not modify singlestep buffer while resuming kprobes/x86: Make boostable flag boolean kprobes/x86: Set kprobes pages readonly kprobes/x86: Use probe_kernel_read instead of memcpy kprobes/x86: Consolidate insn decoder users for copying code arch/x86/include/asm/kprobes.h | 7 +- arch/x86/kernel/kprobes/common.h | 4 + arch/x86/kernel/kprobes/core.c | 149 +++++++++++++++++++------------------- arch/x86/kernel/kprobes/ftrace.c | 2 - arch/x86/kernel/kprobes/opt.c | 13 +++ 5 files changed, 90 insertions(+), 85 deletions(-) -- Masami Hiramatsu (Linaro) <mhira...@kernel.org>
