[PATCH v2 5/6] perf annotate-data: Fix libdw API contract violations

[Ian Rogers <irogers@google.com>]

Check return values of `dwarf_aggregate_size` and `dwarf_formudata`.
Validate `dwarf_diename` before `strdup` to prevent potential crashes.

Fixes: 2bc3cf575a16 ("perf annotate-data: Improve debug message with location info")
Fixes: 4a111cadac85 ("perf annotate-data: Add member field in the data type")
Fixes: 8b1042c425f6 ("perf annotate-data: Set bitfield member offset and size properly")
Fixes: fc044c53b99f ("perf annotate-data: Add dso->data_types tree")
Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/annotate-data.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index 1eff0a27237d..e881a40a4885 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -74,7 +74,8 @@ void pr_debug_type_name(Dwarf_Die *die, enum type_state_kind kind)
 		break;
 	}
 
-	dwarf_aggregate_size(die, &size);
+	if (dwarf_aggregate_size(die, &size) != 0)
+		size = 0;
 
 	strbuf_init(&sb, 32);
 	die_get_typename_from_type(die, &sb);
@@ -250,9 +251,10 @@ static int __add_member_cb(Dwarf_Die *die, void *arg)
 	if (dwarf_aggregate_size(&die_mem, &size) < 0)
 		size = 0;
 
-	if (dwarf_attr_integrate(die, DW_AT_data_member_location, &attr))
-		dwarf_formudata(&attr, &loc);
-	else {
+	if (dwarf_attr_integrate(die, DW_AT_data_member_location, &attr)) {
+		if (dwarf_formudata(&attr, &loc) != 0)
+			loc = 0;
+	} else {
 		/* bitfield member */
 		if (dwarf_attr_integrate(die, DW_AT_data_bit_offset, &attr) &&
 		    dwarf_formudata(&attr, &loc) == 0)
@@ -273,7 +275,9 @@ static int __add_member_cb(Dwarf_Die *die, void *arg)
 				     dwarf_diename(die), (long)bit_size) < 0)
 				member->var_name = NULL;
 		} else {
-			member->var_name = strdup(dwarf_diename(die));
+			const char *name = dwarf_diename(die);
+
+			member->var_name = strdup(name ?: "unknown");
 		}
 
 		if (member->var_name == NULL) {
@@ -370,7 +374,8 @@ static struct annotated_data_type *dso__findnew_data_type(struct dso *dso,
 	if (dwarf_tag(type_die) == DW_TAG_typedef)
 		die_get_real_type(type_die, type_die);
 
-	dwarf_aggregate_size(type_die, &size);
+	if (dwarf_aggregate_size(type_die, &size) != 0)
+		size = 0;
 
 	/* Check existing nodes in dso->data_types tree */
 	key.self.type_name = type_name;
-- 
2.54.0.545.g6539524ca2-goog