On Thu, 21 Jun 2018 12:35:46 +0200 Ingo Molnar <mingo@xxxxxxxxxx> wrote: > > * Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > > > On Tue, 19 Jun 2018 09:31:49 -0700 > > Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: > > > > > On 06/19/2018 09:16 AM, Masami Hiramatsu wrote: > > > > Add a section that explaining how to change the execution > > > > path with kprobes and warnings for some arch. > > > > > > > > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > > > > Cc: Jonathan Corbet <corbet@xxxxxxx> > > > > Cc: linux-doc@xxxxxxxxxxxxxxx > > > > --- > > > > Documentation/kprobes.txt | 20 ++++++++++++++++++++ > > > > 1 file changed, 20 insertions(+) > > > > > > > > diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt > > > > index 3e9e99ea751b..8a98eed1521b 100644 > > > > --- a/Documentation/kprobes.txt > > > > +++ b/Documentation/kprobes.txt > > > > @@ -80,6 +80,26 @@ After the instruction is single-stepped, Kprobes executes the > > > > "post_handler," if any, that is associated with the kprobe. > > > > Execution then continues with the instruction following the probepoint. > > > > > > > > > > Hi, > > > I have a few small suggestions... > > > > Hi Randy, > > > > Thank you for your suggestions! > > All of those are good to me. I'll fix it:) > > Could you please send a delta patch on top of your v6 series, with Randy credited, > etc? Ok, Here's the delta patch. > > I've applied your series and will push it out once it passes all testing. Thanks! >From 103fc58ece99475b855e065bd48d780697b93bbc Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Date: Fri, 22 Jun 2018 15:05:49 +0900 Subject: [PATCH] Documentation/kprobes: Fix typo in Changing Execution Path section Fix typo and clean it up according to the comment from Randy. Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Suggested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> --- Documentation/kprobes.txt | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt index 13d8efd..10f4499 100644 --- a/Documentation/kprobes.txt +++ b/Documentation/kprobes.txt @@ -83,22 +83,22 @@ Execution then continues with the instruction following the probepoint. Changing Execution Path ----------------------- -Since the kprobes can probe into a running kernel code, it can change -the register set, including instruction pointer. This operation -requires maximum attention, such as keeping the stack frame, recovering -execution path etc. Since it is operated on running kernel and need deep -knowladge of the archtecture and concurrent computing, you can easily -shot your foot. +Since kprobes can probe into a running kernel code, it can change the +register set, including instruction pointer. This operation requires +maximum care, such as keeping the stack frame, recovering the execution +path etc. Since it operates on a running kernel and needs deep knowledge +of computer architecture and concurrent computing, you can easily shoot +your foot. If you change the instruction pointer (and set up other related -registers) in pre_handler, you must return !0 so that the kprobes -stops single stepping and just returns to given address. +registers) in pre_handler, you must return !0 so that kprobes stops +single stepping and just returns to the given address. This also means post_handler should not be called anymore. -Note that this operation may be harder on some architectures which -use TOC (Table of Contents) for function call, since you have to -setup new TOC for your function in your module, and recover old -one after back from it. +Note that this operation may be harder on some architectures which use +TOC (Table of Contents) for function call, since you have to setup a new +TOC for your function in your module, and recover the old one after +returning from it. Return Probes ------------- -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
