Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

From: Namhyung Kim
Date: Sun Mar 04 2018 - 21:28:28 EST


Hi Masami,

On Fri, Mar 02, 2018 at 03:32:29PM +0900, Masami Hiramatsu wrote:
> On Fri, 2 Mar 2018 13:49:51 +0900
> Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> > Hi Masami,
> >
> > On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > > In Documentation/trace/kprobetrace.txt, it says
> > >
> > > @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
> > >
> > > However, the parser doesn't parse minus offset correctly, since
> > > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > > unsigned") drops minus ("-") offset support for kprobe probe
> > > address usage.
> > >
> > > This fixes the traceprobe_split_symbol_offset() to parse minus
> > > offset again with checking the offset range, and add a minus
> > > offset check in kprobe probe address usage.
> >
> > It now parses a minus offset but doesn't allow it, right?
>
> No, split_symbol_offset() is used for 2 cases
> - kprobe-event probe point
> - kporbe-event symbol-based argument
>
> Former one doesn't accept a minus offset, but latter accepts it.

Ah, ok then.

Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>


>
> (Frankly to say, I guess no one care about supporting minus offset :P)

:)

Thanks,
Namhyung