Re: [PATCH] error-injection: Add prompt for function error injection

Masami Hiramatsu
2022-11-21T22:24:17Z

On Mon, 21 Nov 2022 10:44:03 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
>
> The config to be able to inject error codes into any function annotated
> with ALLOW_ERROR_INJECTION() is enabled when CONFIG_FUNCTION_ERROR_INJECTION
> is enabled. But unfortunately, this is always enabled on x86 when KPROBES
> is enabled, and there's no way to turn it off.
>
> As kprobes is useful for observability of the kernel, it is useful to have
> it enabled in production environments. But error injection should be
> avoided. Add a prompt to the config to allow it to be disabled even when
> kprobes is enabled, and get rid of the "def_bool y".
>
> This is a kernel debug feature (it's in Kconfig.debug), and should have
> never been something enabled by default.
>

Oops, thanks for update. Yes, it should not be enabled in the production system.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,

> Cc: stable@vger.kernel.org
> Fixes: 540adea3809f6 ("error-injection: Separate error-injection from kprobe")
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
> lib/Kconfig.debug | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index c3c0b077ade3..9ee72d8860c3 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1874,8 +1874,14 @@ config NETDEV_NOTIFIER_ERROR_INJECT
> If unsure, say N.
>
> config FUNCTION_ERROR_INJECTION
> - def_bool y
> + bool "Fault-injections of functions"
> depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
> + help
> + Add fault injections into various functions that are annotated with
> + ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
> + value of theses functions. This is useful to test error paths of code.
> +
> + If unsure, say N
>
> config FAULT_INJECTION
> bool "Fault-injection framework"
> --
> 2.35.1
>

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>