Re: [PATCH bpf-next v3 1/5] tracing/kprobe: bpf: Check error injectable event is on function entry

Josef Bacik
2018-01-10T15:21:41Z

On Wed, Jan 10, 2018 at 07:17:06PM +0900, Masami Hiramatsu wrote:
> Check whether error injectable event is on function entry or not.
> Currently it checks the event is ftrace-based kprobes or not,
> but that is wrong. It should check if the event is on the entry
> of target function. Since error injection will override a function
> to just return with modified return value, that operation must
> be done before the target function starts making stackframe.
>
> As a side effect, bpf error injection is no need to depend on
> function-tracer. It can work with sw-breakpoint based kprobe
> events too.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>

Reviewed-by: Josef Bacik <jbacik@fb.com>

Thanks,

Josef