On 04/26/2019 11:49 AM, Joe Lawrence wrote:
> On 4/26/19 2:40 PM, Mario Smarduch wrote:
>>
>> A side question regarding calling the new function after it's patched
>> and performance. Is the similar trampoline mechanism used when a
>> ftrace hook is set? Meaning pt_regs is presented to hook and 'rip' is
>> changed?
>>
>
> Yes. So technically the old function does get invoked, but at its very
> beginning, the ftrace handler routes off to the new function... and as
> you guessed, its 'rip' is modified to return back to the original caller
> and not the old function.
>
> The "kpatch in action" video on the github page has a diagram similar to
> this one for kGraft:
>
> https://www.suse.com/c/wp-content/uploads/2018/03/Live-Patching-Diagram.png
>
>
> -- Joe
Got it thanks for you help.
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