Re: [PATCH] stop_machine: Mark functions as notrace

From: Steven Rostedt
Date: Fri Oct 30 2020 - 20:28:26 EST


On Fri, 30 Oct 2020 14:47:56 -0700
Atish Patra <atishp@xxxxxxxxxxxxxx> wrote:

> > Look at arm64, they __kprobes flag and I guess it would also prevent
> > ftrace call site.
> >
>
> Are you sure about that ? __kprobes puts the code in .kprobes.text section
> which is under whitelist sections in recordmcount.pl & recordmcount.c.

Correct, ftrace can trace functions marked with __kprobes. That said,
the instruction you are looking at here, is in a file that is
blacklisted from recordmcount.

CFLAGS_REMOVE_insn.o = $(CC_FLAGS_FTRACE)

All ftrace flags are removed from the compiling of insn.c, and every
function in that file will not be traced.

-- Steve