On Thu, 9 Feb 2017 18:06:44 +0000 Russell King - ARM Linux <[email protected]> wrote:
> On Thu, Feb 09, 2017 at 12:13:22PM -0500, Steven Rostedt wrote: > > Then came along live kernel patching, which I believe this series is > > trying to support. What is needed by pt_regs is a way to "hijack" the > > function being called to instead call the patched function. That is, > > ftrace is not being used for tracing, but in reality, being used to > > modify the running kernel. It is being used to change what function > > gets called. ftrace is just a hook for that mechanism. > > So, would I be correct to assume that the only parts of pt_regs that > would be touched are those which contain arguments to the function, > and the register which would contain the return value? > For live kernel patching, perhaps. But for kprobes, I think they can touch anything. Matters what the creater of the kprobe wanted to do. -- Steve
