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Re: [PATCH 4/5 v3] ftrace/x86_32: Clean up ftrace_regs_caller




On Thu, 16 Mar 2017 12:30:25 -0700
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, Mar 16, 2017 at 12:24 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> >         popl    %ds
> >         popl    %es
> >         popl    %fs
> >         popl    %gs  
> 
> Do you even need these? Can they be changed by ftrace?

ftrace no, kprobes, maybe.

> 
> And see the previous email about not touching the original location at
> all, adn just duplicating that entry, avoiding all the need for
> shuffling. I *really* hope that ftrace doesn't depend on changing the
> return %eip on the stack. That would be truly nasty.

How do you think the live patching works?

-- Steve