[PATCH 5.4 248/434] perf probe: Fix to probe an inline function which has no entry pc

Greg Kroah-Hartman
2019-12-29T17:51:21Z

From: Masami Hiramatsu <mhiramat@kernel.org>

[ Upstream commit eb6933b29d20bf2c3053883d409a53f462c1a3ac ]

Fix perf probe to probe an inlne function which has no entry pc
or low pc but only has ranges attribute.

This seems very rare case, but I could find a few examples, as
same as probe_point_search_cb(), use die_entrypc() to get the
entry address in probe_point_inline_cb() too.

Without this patch:

# perf probe -D __amd_put_nb_event_constraints
Failed to get entry address of __amd_put_nb_event_constraints.
Probe point '__amd_put_nb_event_constraints' not found.
Error: Failed to add events.

With this patch:

# perf probe -D __amd_put_nb_event_constraints
p:probe/__amd_put_nb_event_constraints amd_put_event_constraints+43

Committer testing:

Before:

[root@quaco ~]# perf probe -D __amd_put_nb_event_constraints
Failed to get entry address of __amd_put_nb_event_constraints.
Probe point '__amd_put_nb_event_constraints' not found.
Error: Failed to add events.
[root@quaco ~]#

After:

[root@quaco ~]# perf probe -D __amd_put_nb_event_constraints
p:probe/__amd_put_nb_event_constraints _text+33789
[root@quaco ~]#

Fixes: 4ea42b181434 ("perf: Add perf probe subcommand, a kprobe-event setup helper")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199320336.8075.16189530425277588587.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/probe-finder.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 7c8d30fb2b99..7857ae7a10b7 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -942,7 +942,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
ret = find_probe_point_lazy(in_die, pf);
else {
/* Get probe address */
- if (dwarf_entrypc(in_die, &addr) != 0) {
+ if (die_entrypc(in_die, &addr) != 0) {
pr_warning("Failed to get entry address of %s.\n",
dwarf_diename(in_die));
return -ENOENT;
--
2.20.1