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[4.9,050/171] perf probe: Fix to find range-only function instance

Message ID 20200102220553.918514376@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Jan. 2, 2020, 10:06 p.m. UTC 
From: Masami Hiramatsu <mhiramat@kernel.org>

[ Upstream commit b77afa1f810f37bd8a36cb1318178dfe2d7af6b6 ]

Fix die_is_func_instance() to find range-only function instance.

In some case, a function instance can be made without any low PC or
entry PC, but only with address ranges by optimization.  (e.g. cold text
partially in "text.unlikely" section) To find such function instance, we
have to check the range attribute too.

Fixes: e1ecbbc3fa83 ("perf probe: Fix to handle optimized not-inlined functions")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157190835669.1859.8368628035930950596.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 | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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Patch

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 41e068e94349..3d0a9e09d00a 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -328,10 +328,14 @@  bool die_is_func_def(Dwarf_Die *dw_die)
 bool die_is_func_instance(Dwarf_Die *dw_die)
 {
 	Dwarf_Addr tmp;
+	Dwarf_Attribute attr_mem;
 
 	/* Actually gcc optimizes non-inline as like as inlined */
-	return !dwarf_func_inline(dw_die) && dwarf_entrypc(dw_die, &tmp) == 0;
+	return !dwarf_func_inline(dw_die) &&
+	       (dwarf_entrypc(dw_die, &tmp) == 0 ||
+		dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL);
 }
+
 /**
  * die_get_data_member_location - Get the data-member offset
  * @mb_die: a DIE of a member of a data structure