Re: [PATCH] tracing/kprobes: Do the notrace functions check without kprobes on ftrace

[Masami Hiramatsu <mhiramat@kernel.org>]

On Thu, 7 Jan 2021 09:13:30 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed,  6 Jan 2021 12:20:40 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > Enable the notrace function check on the architecture which doesn't
> > support kprobes on ftrace. This notrace function check is not only
> > for the kprobes on ftrace but also sw-breakpoint based kprobes.
> > Thus there is no reason to limit this check for the arch which
> > supports kprobes on ftrace.
> > 
> > This also changes the dependency of Kconfig. Because kprobe event
> > uses the function tracer's address list for identifying notrace
> > function, if the CONFIG_FUNCTION_TRACER=n, it can not check whether
> > the target function is notrace or not.
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> > ---
> 
> Fails to build with:
> 
> kernel/trace/trace_kprobe.c: In function ‘__within_notrace_func’:
> kernel/trace/trace_kprobe.c:453:10: error: implicit declaration of function ‘ftrace_location_range’; did you mean ‘ftrace_location’? [-Werror=implicit-function-declaration]
>   453 |  return !ftrace_location_range(addr, addr + size - 1);
>       |          ^~~~~~~~~~~~~~~~~~~~~
>       |          ftrace_location
> 

Oops, it depends on CONFIG_DYNAMIC_FTRACE=y instead of CONFIG_FUNCTION_TRACER.

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>