perf dwarf-aux: Fix __die_find_scope_cb() for namespaces

Currently __die_find_scope_cb() goes to check siblings when the DIE
doesn't include the given PC.

However namespaces don't have a PC and could contain children that have
that PC.

When we encounter a namespace, we should check both its children and
siblings.

Reviewed-by: Namhyung Kim <[e-mail]>
Signed-off-by: Zecheng Li <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Xu Liu <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/dwarf-aux.c

···
 static int __die_find_scope_cb(Dwarf_Die *die_mem, void *arg)
 {
 	struct find_scope_data *data = arg;
+	int tag = dwarf_tag(die_mem);
 
 	if (dwarf_haspc(die_mem, data->pc)) {
 		Dwarf_Die *tmp;
···
 		data->nr++;
 		return DIE_FIND_CB_CHILD;
 	}
+
+	/*
+	 * If the DIE doesn't have the PC, we still need to check its children
+	 * and siblings if it's a container like a namespace.
+	 */
+	if (tag == DW_TAG_namespace)
+		return DIE_FIND_CB_CONTINUE;
+
 	return DIE_FIND_CB_SIBLING;
 }