On Mon, 15 Aug 2022 11:16:58 -0400 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > It sounds that you've invented nop5 and kernel's ability > > to replace nop5 with a jump or call. > > Actually I did invent it. > > https://lore.kernel.org/lkml/20080210072109.GR4100@xxxxxxx/ > > > I'm the one that introduced the code to convert mcount into the 5 byte nop, > and did the research and development to make it work at run time. I had one > hiccup along the way that caused the e1000e network card breakage. > > The "daemon" approach was horrible, and then I created the recordmcount.pl > perl script to accomplish the same thing at compile time. I guess you were not paying attention to my talk at the Kernel Recipes I invited you to in 2019. The talk I gave was the history of how fentry came about. https://kernel-recipes.org/en/2019/talks/ftrace-where-modifying-a-running-kernel-all-started/ ;-) -- Steve
