Re: [PATCH v3] tracing: precise log info for kretprobe addr err

[Steven Rostedt]

On Tue, 26 Jan 2021 21:20:59 +0100
Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> > No, not wrong. Even offset != 0, if the symbol exists in the kernel,
> > kprobe_on_func_entry() will check it.  
> 
> Yes, but unless I am totally confused... if kprobe_on_func_entry() returns false,
> then trace_kprobe_create() should fail with BAD_RETPROBE even if offset == 0 ?

>From what I understand. kprobe_on_func_entry() can return false if you pass
in: "MOD:not_yet_loaded_module_func", but this is OK, because when the
module is loaded, and the "not_yet_loaded_module_func" exists, the
kretprobe will then be added.

The strchr(symbol,":") check is to see if "MOD:" (or some other ":" command)
is in the name, and we don't want it to fail if it is. Which is why we
should have that commented.

-- Steve