Re: [PATCH for-next v2] tracing/kprobes: Add symbol counting check when module loads

[Google]

On Tue, 16 Apr 2024 00:47:26 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Mon, 15 Apr 2024 18:40:23 +0900
> "Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:
> 
> > Check the number of probe target symbols in the target module when
> > the module is loaded. If the probe is not on the unique name symbols
> > in the module, it will be rejected at that point.
> > 
> > Note that the symbol which has a unique name in the target module,
> > it will be accepted even if there are same-name symbols in the
> > kernel or other modules,
> 
> This says what it does, but doesn't explain why it is doing it.
> What's the purpose of this patch?

Thank you for pointing it out, I just reused the description which I
sent last year. It needs to be updated.

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Currently, kprobe event checks whether the target symbol name is
unique, so that it does not put a probe on unexpected place. But this
skips the check if the target is on a module. This fixes the issue
by checking the symbol is unique in the target module if the target
is on a module.
-----

Thanks!

> 
> -- Steve


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>