Re: [PATCH perf/core 4/4] perf-probe: Find probe events without target module

Masami Hiramatsu
2017-01-10T15:55:12Z

On Sat, 7 Jan 2017 14:28:42 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Find probe events without -m "module" option. If perf-probe
> failed to find given function in kernel image, it tries to
> find same symbol and module in kallsyms, and retry search
> in the found module. E.g.
>
> # perf probe -D i915_capabilities
> p:probe/i915_capabilities i915:i915_capabilities+0
>
> Note: without -m option, perf probe can not find inlined
> function since there is no symbol information in kallsyms.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/util/probe-event.c | 74 ++++++++++++++++++++++++++++++-----------
> 1 file changed, 55 insertions(+), 19 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 6a6f44d..09bd093 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -858,11 +858,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
>
> debuginfo__delete(dinfo);
>
> - if (ntevs == 0) { /* No error but failed to find probe point. */
> - pr_warning("Probe point '%s' not found.\n",
> - synthesize_perf_probe_point(&pev->point));
> - return -ENOENT;
> - } else if (ntevs < 0) {
> + if (ntevs < 0) {
> /* Error path : ntevs < 0 */
> pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs);
> if (ntevs == -EBADF)
> @@ -2073,8 +2069,10 @@ static int find_perf_probe_point_from_map(struct probe_trace_point *tp,
> } else {
> if (tp->symbol && !addr) {
> if (kernel_get_symbol_address_by_name(tp->symbol,
> - &addr, true, false) < 0)
> + &addr, true, false) < 0) {
> + ret = 0;
> goto out;

Oops, I've found that this is not needed and breaks --list result.
I'll update it.

Thanks.

--
Masami Hiramatsu <mhiramat@kernel.org>