Re: [PATCH] ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()

[Peter Zijlstra]

On Tue, Oct 18, 2022 at 07:28:29AM -0700, Kees Cook wrote:

> Thanks for solving this! Just for future archeology, can you include
> the splat (I assume you hit a CFI splat) in the commit log, and/or how
> you triggered the problem? I usually find it helpful in trying to fix
> similar issues later, etc.

Unfortunately I didn't save it; it was a while ago (I sorta lost track
of this fix for a while since it was stuffed in my fineibt queue).

But Mark ran it today to confirm on arm64 and there it looks like
(harvested from IRC):

  [    3.153082] CFI failure at ftrace_return_to_handler+0xac/0x16c (target: ftrace_stub+0x0/0x14; expected type: 0x0a5d5347)

I think simply enabling the ftrace boot time tests is enough to trigger
this.