Messages in this thread |  | | Date | Sun, 11 Dec 2022 12:27:31 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH] ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack |
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On Fri, 9 Dec 2022 15:34:02 +0100 Ard Biesheuvel <ardb@kernel.org> wrote:
> The recent switch on arm64 from DYNAMIC_FTRACE_WITH_REGS to > DYNAMIC_FTRACE_WITH_ARGS failed to take into account that we currently > require the former in order to allow the function graph tracer to be > enabled in combination with shadow call stacks. This means that this is > no longer permitted at all, in spite of the fact that either flavour of > ftrace works perfectly fine in this combination. > > Given that arm64 is the only arch that implements shadow call stacks in > the first place, let's update the condition to just reflect the arm64 > change. When other architectures adopt shadow call stack support, this > can be revisited if needed.
This brings a question. Is the SCS safe if kretprobe(rethook) is enabled? it also changes the stack entry after a calling function.
Thank you,
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > --- > arch/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 072a1b39e3afd0d1..683f365b5e31c856 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -635,7 +635,7 @@ config ARCH_SUPPORTS_SHADOW_CALL_STACK > config SHADOW_CALL_STACK > bool "Shadow Call Stack" > depends on ARCH_SUPPORTS_SHADOW_CALL_STACK > - depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER > + depends on DYNAMIC_FTRACE_WITH_ARGS || !FUNCTION_GRAPH_TRACER > help > This option enables the compiler's Shadow Call Stack, which > uses a shadow stack to protect function return addresses from > -- > 2.35.1 >
-- Masami Hiramatsu (Google) <mhiramat@kernel.org>
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