release/5.2.33/perf-probe-Fix-to-find-range-only-function-instance.patch

From 2698db083dbec99ba6568e4df0456240cda83214 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Thu, 24 Oct 2019 18:12:36 +0900
Subject: [PATCH] perf probe: Fix to find range-only function instance

commit b77afa1f810f37bd8a36cb1318178dfe2d7af6b6 upstream.

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: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 218bfea8f8a8..4ddb772a9bab 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -317,10 +317,14 @@ 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
-- 
2.7.4