Re: [PATCH] kprobes: Print an error if probe is rejected

From: Naveen N. Rao
Date: Mon Jun 21 2021 - 05:37:29 EST

Hi Masami,

Masami Hiramatsu wrote:
Hi Naveen,

On Mon, 14 Jun 2021 21:00:52 +0530
"Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> wrote:

Steven Rostedt wrote:
> On Fri, 11 Jun 2021 19:25:38 +0530
> "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> wrote:
> >> We also have perf_event_open() as an interface to add probes, and I >> don't think it would be helpful to require all tools to utilize the >> error log from tracefs for this purpose.
> > The there should be a perf interface to read the errors. I agree with
> Masami. Let's not have console logs for probe errors.

Ok, understood.

Will you update this?

Not sure if you are asking about error logging with perf_event_open(), or about reading error_log from tracefs.

For perf_event_open(), I think we will just need to return the error code, and interpret the return value in userspace. I don't think there is any other way to pass error log or strings back from the kernel.

I will update this series to return the correct return value as suggested.