(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,
> 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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>
>
>
--
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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