Messages in this thread | | | Date | Tue, 11 Apr 2017 14:44:13 +0900 | From | Masami Hiramatsu <> | Subject | Re: [RFC PATCH tip/master V3 0/8] kprobes/x86: Make kprobes instruction buffers read-only |
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On Wed, 29 Mar 2017 13:55:44 +0900 Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 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) <mhiramat@kernel.org>
-- Masami Hiramatsu <mhiramat@kernel.org>
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