Messages in this thread | | | Date | Thu, 9 Feb 2017 13:14:14 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCHv3] arm: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS |
| |
On Thu, 9 Feb 2017 18:06:44 +0000 Russell King - ARM Linux <linux@armlinux.org.uk> 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
| |