From c116d3d93ba2fe9043726770151a138191a6151a Mon Sep 17 00:00:00 2001
From: Ovidiu Sas <osas@voipembedded.com>
Date: Tue, 7 Apr 2026 13:23:31 -0400
Subject: [PATCH] lib/dbg: enhance opensips debug capabilites with backtrace  -
 sometimed the file/function/line is not enough to troubleshoot  - a backtrace
 gives more details about the code path

---
 lib/dbg/struct_hist.c | 48 +++++++++++++++++++++++++++++++++++++++++++
 lib/dbg/struct_hist.h |  8 ++++++++
 2 files changed, 56 insertions(+)

diff --git a/lib/dbg/struct_hist.c b/lib/dbg/struct_hist.c
index ff219e52571..faa8cdf787e 100644
--- a/lib/dbg/struct_hist.c
+++ b/lib/dbg/struct_hist.c
@@ -21,6 +21,12 @@
 #include <stdio.h>
 #include <stdarg.h>
 
+#ifdef BACKTRACE_DBG
+#include <stdlib.h>
+#include <string.h>
+#include <execinfo.h>
+#endif
+
 #include "struct_hist.h"
 
 #include "../../mem/shm_mem.h"
@@ -78,6 +84,9 @@ static inline const char *verb2str(enum struct_hist_verb verb)
 
 static void sh_unref_unsafe(struct struct_hist *sh, osips_free_f free_f);
 static void sh_free(struct struct_hist *sh, osips_free_f free_f);
+#ifdef BACKTRACE_DBG
+static void sh_log_backtrace(const struct struct_hist_action *act);
+#endif
 
 struct struct_hist_list *_shl_init(char *obj_name, int window_size,
 			int auto_logging, int init_actions_sz, osips_malloc_f malloc_f)
@@ -213,6 +222,9 @@ static void _sh_flush(struct struct_hist *sh, int do_logging)
 			        sh->actions[i].t,
 			        sh->actions[i].pid,
 			        sh->actions[i].log);
+#ifdef BACKTRACE_DBG
+			        sh_log_backtrace(&sh->actions[i]);
+#endif
 		}
 	}
 
@@ -220,6 +232,29 @@ static void _sh_flush(struct struct_hist *sh, int do_logging)
 	sh->len = 0;
 }
 
+#ifdef BACKTRACE_DBG
+static void sh_log_backtrace(const struct struct_hist_action *act)
+{
+	char **symbols;
+	int i;
+
+	if (act->bt_size <= 0)
+		return;
+
+	symbols = backtrace_symbols(act->bt, act->bt_size);
+	if (!symbols) {
+		for (i = 0; i < act->bt_size; i++)
+			LM_INFO("      bt[%d]: %p\n", i, act->bt[i]);
+		return;
+	}
+
+	for (i = 0; i < act->bt_size; i++)
+		LM_INFO("      bt[%d]: %s\n", i, symbols[i]);
+
+	free(symbols);
+}
+#endif
+
 void sh_flush(struct struct_hist *sh)
 {
 	lock_get(&sh->wlock);
@@ -254,6 +289,9 @@ int _sh_log(osips_realloc_f realloc_f, struct struct_hist *sh,
 {
 	va_list ap;
 	int n;
+#ifdef BACKTRACE_DBG
+	int bt_size;
+#endif
 	struct struct_hist_action *new, *act;
 
 	if (!sh)
@@ -290,6 +328,16 @@ int _sh_log(osips_realloc_f realloc_f, struct struct_hist *sh,
 	act->t = get_uticks();
 	act->pid = my_pid();
 
+#ifdef BACKTRACE_DBG
+	bt_size = backtrace(act->bt, SH_BACKTRACE_SIZE);
+	if (bt_size > 1) {
+		memmove(act->bt, act->bt + 1, (bt_size - 1) * sizeof(*act->bt));
+		act->bt_size = bt_size - 1;
+	} else {
+		act->bt_size = 0;
+	}
+#endif
+
 	n = vsnprintf(act->log, MAX_SHLOG_SIZE, fmt, ap);
 	lock_release(&sh->wlock);
 
diff --git a/lib/dbg/struct_hist.h b/lib/dbg/struct_hist.h
index c45cb6f5df1..109893c636b 100644
--- a/lib/dbg/struct_hist.h
+++ b/lib/dbg/struct_hist.h
@@ -24,6 +24,10 @@
 #include "../../timer.h"
 #include "../../mem/mem_funcs.h"
 
+#ifdef BACKTRACE_DBG
+#define SH_BACKTRACE_SIZE 16
+#endif
+
 /**
  * Generic struct debugging support.  Some major use cases:
  *   - troubleshooting bugs related to reference counted structures, including:
@@ -81,6 +85,10 @@ struct struct_hist_action {
 	enum struct_hist_verb verb;
 	utime_t t;
 	int pid;
+#ifdef BACKTRACE_DBG
+	int bt_size;
+	void *bt[SH_BACKTRACE_SIZE];
+#endif
 	char log[MAX_SHLOG_SIZE];
 };