Messages in this thread | | | Date | Tue, 11 Jul 2023 08:50:21 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [RFC PATCH 1/2] kprobes: Prohibit probing on CFI preamble symbol |
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On Mon, 10 Jul 2023 17:37:24 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, Jul 10, 2023 at 09:14:24PM +0900, Masami Hiramatsu (Google) wrote: > > > > +#ifdef CONFIG_CFI_CLANG > > +static bool is_cfi_preamble_symbol(unsigned long addr) > > +{ > > + char symbuf[KSYM_NAME_LEN]; > > + > > + if (lookup_symbol_name(addr, symbuf)) > > + return false; > > + > > + return str_has_prefix("__cfi_", symbuf) > || str_has_prefix("__pfx_", symbol); > > The __pfx_ symbols can happen when !CFI_CLANG but still having > FUNCTION_PADDING_BYTES.
Indeed. Currently __pfx is not probed via tracefs interface because it is notrace function but kprobe itself should also prohibit that.
> > > +} > > +#else > > +#define is_cfi_preamble_symbol(addr) (0) > > +#endif > > As such I think we can do the above unconditionally, without either > there should not be any matching symbols.
OK.
Thank you!
>
-- Masami Hiramatsu (Google) <mhiramat@kernel.org>
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