Em Sat, Feb 28, 2015 at 12:21:05PM +0900, Masami Hiramatsu escreveu:
> (2015/02/28 11:53), Masami Hiramatsu wrote:
> > Warn if given uprobe event accesses memory on older kernel.
> > Until 3.14, uprobe event only supports accessing registers
> > so this warns to upgrade kernel if uprobe-event returns
> > -EINVAL and an argument of the event accesses memory ($stack,
> > @+offset, and +|-offs() symtax).
> >
> > With this patch (on 3.10.0-123.13.2.el7.x86_64);
> > -----
> > # ./perf probe -x ./perf warn_uprobe_event_compat stack=-0\(%sp\)
> > Added new event:
> > Failed to write event: Invalid argument
> > Please upgrade your kernel to at least 3.14 to have access to feature
> > -0(%sp)
> > Error: Failed to add events.
> > -----
> >
>
> Oops,
>
> Suggested-by: Arnaldo Carvalho de Melo <a...@kernel.org>
:-)
Thanks for considering my suggestion and coming up with a patch so
quickly!
I'll test it and merge,
- Arnaldo
> Thanks,
>
> > Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
> > ---
> > tools/perf/util/probe-event.c | 23 +++++++++++++++++++++++
> > 1 file changed, 23 insertions(+)
> >
> > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> > index 7c0e765..1c570c2fa7 100644
> > --- a/tools/perf/util/probe-event.c
> > +++ b/tools/perf/util/probe-event.c
> > @@ -2199,6 +2199,27 @@ static int get_new_event_name(char *buf, size_t len,
> > const char *base,
> > return ret;
> > }
> >
> > +/* Warn if the current kernel's uprobe implementation is old */
> > +static void warn_uprobe_event_compat(struct probe_trace_event *tev)
> > +{
> > + int i;
> > + char *buf = synthesize_probe_trace_command(tev);
> > +
> > + /* Old uprobe event doesn't support memory dereference */
> > + if (!tev->uprobes || tev->nargs == 0 || !buf)
> > + goto out;
> > +
> > + for (i = 0; i < tev->nargs; i++)
> > + if (strglobmatch(tev->args[i].value, "[$@+-]*")) {
> > + pr_warning("Please upgrade your kernel to at least "
> > + "3.14 to have access to feature %s\n",
> > + tev->args[i].value);
> > + break;
> > + }
> > +out:
> > + free(buf);
> > +}
> > +
> > static int __add_probe_trace_events(struct perf_probe_event *pev,
> > struct probe_trace_event *tevs,
> > int ntevs, bool allow_suffix)
> > @@ -2295,6 +2316,8 @@ static int __add_probe_trace_events(struct
> > perf_probe_event *pev,
> > */
> > allow_suffix = true;
> > }
> > + if (ret == -EINVAL && pev->uprobes)
> > + warn_uprobe_event_compat(tev);
> >
> > /* Note that it is possible to skip all events because of blacklist */
> > if (ret >= 0 && tev->event) {
> >
> > --
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> > Please read the FAQ at http://www.tux.org/lkml/
> >
> >
> >
>
>
> --
> Masami HIRAMATSU
> Software Platform Research Dept. Linux Technology Research Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu...@hitachi.com
>
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