[PATCH 5.4 249/434] perf probe: Fix to show ranges of variables in functions without entry_pc

Greg Kroah-Hartman
2019-12-29T18:05:17Z

From: Masami Hiramatsu <mhiramat@kernel.org>

[ Upstream commit af04dd2f8ebaa8fbd46f698714acbf43da14da45 ]

Fix to show ranges of variables (--range and --vars option) in functions
which DIE has only ranges but no entry_pc attribute.

Without this fix:

# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
(No matched variables)

With this fix:

# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
[VAL] int cpu @<clear_tasks_mm_cpumask+[0-35,317-317,2052-2059]>

Committer testing:

Before:

[root@quaco ~]# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
(No matched variables)
[root@quaco ~]#

After:

[root@quaco ~]# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
[VAL] int cpu @<clear_tasks_mm_cpumask+[0-23,23-105,105-106,106-106,1843-1850,1850-1862]>
[root@quaco ~]#

Using it:

[root@quaco ~]# perf probe clear_tasks_mm_cpumask cpu
Added new event:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask with cpu)

You can now use it in all perf tools, such as:

perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1

[root@quaco ~]# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c with cpu)
[root@quaco ~]#
[root@quaco ~]# perf trace -e probe:*cpumask
^C[root@quaco ~]#

Fixes: 349e8d261131 ("perf probe: Add --range option to show a variable's location range")
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/157199323018.8075.8179744380479673672.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/dwarf-aux.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 929b7c0567f4..4b1890204e99 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -997,7 +997,7 @@ static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
bool first = true;
const char *name;

- ret = dwarf_entrypc(sp_die, &entry);
+ ret = die_entrypc(sp_die, &entry);
if (ret)
return ret;

@@ -1060,7 +1060,7 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
bool first = true;
const char *name;

- ret = dwarf_entrypc(sp_die, &entry);
+ ret = die_entrypc(sp_die, &entry);
if (ret)
return ret;

--
2.20.1