From 426575aa3273f77277664ed74637a41cc28ab609 Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Fri, 29 Oct 2021 13:35:35 -0400
Subject: [PATCH] TT#14008 add backtraces for obj* debugging output

Change-Id: I51c6667fc835eedf54a10878bc09620557aa8d22
---
 include/obj.h    | 39 +++++++++++++++++++++++++++++++++++++++
 lib/lib.Makefile |  2 ++
 2 files changed, 41 insertions(+)

diff --git a/include/obj.h b/include/obj.h
index f6c8d9a8c..49b40e24c 100644
--- a/include/obj.h
+++ b/include/obj.h
@@ -22,6 +22,15 @@
 #endif
 
 
+#if OBJ_DEBUG
+#define OBJ_BACKTRACE 1
+#else
+#define OBJ_BACKTRACE 0
+#endif
+
+#if OBJ_BACKTRACE
+#include <execinfo.h>
+#endif
 
 
 struct obj {
@@ -104,6 +113,16 @@ INLINE void __obj_init(struct obj *o, unsigned int size, void (*free_func)(void
 	o->magic = OBJ_MAGIC;
 	o->type = strdup(type);
 	write_log(LOG_DEBUG, "obj_allocX(\"%s\") -> %p [%s:%s:%u]", type, o, file, func, line);
+#if OBJ_BACKTRACE
+	void *bt[4];
+	int addrs = backtrace(bt, 4);
+	char **syms = backtrace_symbols(bt, addrs);
+	if (syms) {
+		for (int i = 0; i < addrs; i++)
+			write_log(LOG_DEBUG, "    obj_allocX caller %i: %s", i, syms[i]);
+	}
+	free(syms);
+#endif
 #endif
 	o->ref = 1;
 	o->free_func = free_func;
@@ -151,6 +170,16 @@ INLINE struct obj *__obj_hold(struct obj *o
 	assert(o->magic == OBJ_MAGIC);
 	write_log(LOG_DEBUG, "obj_hold(%p, \"%s\"), refcnt inc %u -> %u [%s:%s:%u]",
 		o, o->type, g_atomic_int_get(&o->ref), g_atomic_int_get(&o->ref) + 1, file, func, line);
+#if OBJ_BACKTRACE
+	void *bt[4];
+	int addrs = backtrace(bt, 4);
+	char **syms = backtrace_symbols(bt, addrs);
+	if (syms) {
+		for (int i = 0; i < addrs; i++)
+			write_log(LOG_DEBUG, "    obj_hold caller %i: %s", i, syms[i]);
+	}
+	free(syms);
+#endif
 #endif
 	g_atomic_int_inc(&o->ref);
 	return o;
@@ -177,6 +206,16 @@ INLINE void __obj_put(struct obj *o
 	assert(o->magic == OBJ_MAGIC);
 	write_log(LOG_DEBUG, "obj_put(%p, \"%s\"), refcnt dec %u -> %u [%s:%s:%u]",
 		o, o->type, g_atomic_int_get(&o->ref), g_atomic_int_get(&o->ref) - 1, file, func, line);
+#if OBJ_BACKTRACE
+	void *bt[4];
+	int addrs = backtrace(bt, 4);
+	char **syms = backtrace_symbols(bt, addrs);
+	if (syms) {
+		for (int i = 0; i < addrs; i++)
+			write_log(LOG_DEBUG, "    obj_put caller %i: %s", i, syms[i]);
+	}
+	free(syms);
+#endif
 #endif
 	if (!g_atomic_int_dec_and_test(&o->ref))
 		return;
diff --git a/lib/lib.Makefile b/lib/lib.Makefile
index 96b356211..8df39317a 100644
--- a/lib/lib.Makefile
+++ b/lib/lib.Makefile
@@ -49,6 +49,8 @@ ifeq ($(DBG),yes)
 CFLAGS+=	-D__DEBUG=1
 endif
 
+# keep debugging symbols for backtrace_symbols()
+LDFLAGS += -rdynamic
 
 ifneq ($(DBG),yes)
   ifeq (,$(filter $(CFLAGS),-O0))