Re: [PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller

From: Steven Rostedt
Date: Mon Feb 14 2022 - 16:34:39 EST


On Mon, 14 Feb 2022 22:54:23 +0530
"Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> wrote:

> For x86, commit 0c0593b45c9b4e ("x86/ftrace: Make function graph use
> ftrace directly") also adds recursion check before the call to
> function_graph_enter() in prepare_ftrace_return(). Do we need that on
> powerpc as well?

Yes. The function_graph_enter() does not provide any recursion protection,
so if it were to call something that gets function graph traced, it will
crash the machine.

-- Steve