Index: funcs/func_channel.c
===================================================================
--- funcs/func_channel.c	(revision 94934)
+++ funcs/func_channel.c	(working copy)
@@ -71,6 +71,15 @@
 		ast_copy_string(buf, ast_getformatname(chan->readformat), len);
 	else if (!strcasecmp(data, "audiowriteformat"))
 		ast_copy_string(buf, ast_getformatname(chan->writeformat), len);
+	else if (!strcasecmp(data, "trace")) {
+		struct ast_datastore *datastore;
+		struct ast_chan_trace_data *traced;
+		ast_channel_lock(chan);
+		datastore = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
+		traced = datastore ? datastore->data : NULL;
+		ast_copy_string(buf, traced && traced->enabled ? "1" : "0", len);
+		ast_channel_unlock(chan);
+	}
 	else if (!strcasecmp(data, "tonezone") && chan->zone)
 		locked_copy_string(chan, buf, chan->zone->country, len);
 	else if (!strcasecmp(data, "language"))
@@ -105,6 +114,23 @@
 		locked_string_field_set(chan, language, value);
 	else if (!strcasecmp(data, "musicclass"))
 		locked_string_field_set(chan, musicclass, value);
+	else if (!strcasecmp(data, "trace")) {
+		struct ast_datastore *datastore;
+		struct ast_chan_trace_data *traced;
+		ast_channel_lock(chan);
+		datastore = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
+		traced = datastore ? datastore->data : NULL;
+		if (ast_true(value)) 
+			ret = ast_channel_enable_context_trace(chan, traced);
+		else if (ast_false(value)) {
+			if (traced)
+				traced->enabled = 0;
+		} else {
+			ret = -1;
+			ast_log(LOG_WARNING, "Invalid value for CHANNEL(trace).");
+		}	
+		ast_channel_unlock(chan);
+	}
 	else if (!strcasecmp(data, "tonezone")) {
 		struct ind_tone_zone *new_zone;
 		if (!(new_zone = ast_get_indication_zone(value))) {
@@ -156,6 +182,7 @@
 		"R/W	tonezone           zone for indications played\n"
 		"R/W	txgain             set txgain level on channel drivers that support it\n"
 		"R/O	videonativeformat  format used natively for video\n"
+		"R/W	trace              whether or not context tracing is enabled\n"
 		"\n"
 		"chan_sip provides the following additional options:\n"
 		"R/O    rtpqos             Get QOS information about the RTP stream\n"
Index: include/asterisk/channel.h
===================================================================
--- include/asterisk/channel.h	(revision 94934)
+++ include/asterisk/channel.h	(working copy)
@@ -226,6 +226,20 @@
 	int cid_tns;		/*!< Callerid Transit Network Select */
 };
 
+/*! \brief Structure to hold channel context trace data */
+struct ast_chan_trace_data {
+	int enabled;
+	AST_LIST_HEAD_NOLOCK(, ast_chan_trace) trace;
+};
+
+/*! \brief Structure to save contexts where an ast_chan has been into */
+struct ast_chan_trace {
+	char context[AST_MAX_CONTEXT];
+	char exten[AST_MAX_EXTENSION];
+	int priority;
+	AST_LIST_ENTRY(ast_chan_trace) entry;
+};
+
 /*! \brief 
 	Structure to describe a channel "technology", ie a channel driver 
 	See for examples:
@@ -355,6 +369,11 @@
  */
 extern unsigned long global_fin, global_fout;
 
+/*!
+ * Datastore info for channel context traces
+ */
+extern const struct ast_datastore_info ast_chan_trace_datastore_info;
+
 enum ast_channel_adsicpe {
 	AST_ADSI_UNKNOWN,
 	AST_ADSI_AVAILABLE,
@@ -820,6 +839,12 @@
  */
 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
 
+/*! \brief Update context trace on channel. It MUST be called only if the channel trace is enabled */
+int ast_channel_update_trace(struct ast_channel *chan, struct ast_chan_trace_data *traced);
+
+/*! \brief Enable tracing in the channel. Must be called with the channel locked */
+int ast_channel_enable_context_trace(struct ast_channel *chan, struct ast_chan_trace_data *traced);
+
 /*! \brief Hang up a channel  
  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
  * performs all stream stopping, etc, on the channel that needs to end.
Index: include/asterisk/pbx.h
===================================================================
--- include/asterisk/pbx.h	(revision 94934)
+++ include/asterisk/pbx.h	(working copy)
@@ -25,6 +25,7 @@
 
 #include "asterisk/sched.h"
 #include "asterisk/chanvars.h"
+#include "asterisk/channel.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
@@ -807,6 +808,11 @@
 /*!
  * \note Will lock the channel.
  */
+int pbx_builtin_serialize_trace(struct ast_channel *chan, struct ast_str **buf, struct ast_chan_trace_data *traced);
+
+/*!
+ * \note Will lock the channel.
+ */
 const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name);
 
 /*!
Index: main/channel.c
===================================================================
--- main/channel.c	(revision 94934)
+++ main/channel.c	(working copy)
@@ -315,6 +315,21 @@
 	AST_CLI_DEFINE(handle_cli_core_show_channeltype,  "Give more details on that channel type")
 };
 
+static void ast_chan_trace_destroy_cb(void *data)
+{
+	struct ast_chan_trace *trace;
+	struct ast_chan_trace_data *traced = data;
+	while ((trace = AST_LIST_REMOVE_HEAD(&traced->trace, entry))) {
+		ast_free(trace);
+	}
+	ast_free(traced);
+}
+
+const struct ast_datastore_info ast_chan_trace_datastore_info = {
+	.type = "ChanTrace",
+	.destroy = ast_chan_trace_destroy_cb
+};
+
 /*! \brief Checks to see if a channel is needing hang up */
 int ast_check_hangup(struct ast_channel *chan)
 {
@@ -1398,6 +1413,64 @@
 	clone->rawreadformat = clone->nativeformats;
 }
 
+/*! \brief Update context trace on channel. It MUST be called only if the channel trace is enabled */
+int ast_channel_update_trace(struct ast_channel *chan, struct ast_chan_trace_data *traced)
+{
+	struct ast_datastore *datastore;
+	struct ast_chan_trace *trace;
+	/* if the trace data structure was not specified, we search it */
+	if (!traced) {
+		datastore = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
+		if (!datastore) {
+			ast_log(LOG_ERROR, "No datastore in channel for context traces.\n");
+			return -1;
+		} else
+			traced = datastore->data;
+	}
+	/* If we already started the trace and the last saved context does not match the current one
+	   OR we have trace enabled and no context saved so far,
+	   then save the current context */
+	if ((!AST_LIST_EMPTY(&traced->trace) && strcasecmp(AST_LIST_FIRST(&traced->trace)->context, chan->context)) || 
+	    (AST_LIST_EMPTY(&traced->trace))) {
+		/* Just do some debug logging */
+		if (AST_LIST_EMPTY(&traced->trace))
+			ast_log(LOG_DEBUG, "Setting initial trace context to %s\n", chan->context);
+		else
+			ast_log(LOG_DEBUG, "Changing trace context from %s to %s\n", AST_LIST_FIRST(&traced->trace)->context, chan->context);
+		/* alloc or bail out */
+		trace = ast_malloc(sizeof(*trace));
+		if (!trace) 
+			return -1;
+		/* save the current location and store it in the trace list */
+		ast_copy_string(trace->context, chan->context, sizeof(trace->context));
+		ast_copy_string(trace->exten, chan->exten, sizeof(trace->exten));
+		trace->priority = chan->priority;
+		AST_LIST_INSERT_HEAD(&traced->trace, trace, entry);
+	}
+	return 0;
+}
+
+/*! \brief Enable tracing in the channel. Must be called with the channel locked */
+int ast_channel_enable_context_trace(struct ast_channel *chan, struct ast_chan_trace_data *traced)
+{
+	struct ast_datastore *datastore;
+	/* if there is no trace data structure, we should allocate one to enable tracing */
+	if (!traced) {
+		datastore = ast_channel_datastore_alloc(&ast_chan_trace_datastore_info, "ChanTrace");
+		if (!datastore) 
+			return -1;
+		traced = ast_calloc(1, sizeof(*traced));
+		if (!traced)
+			return -1;
+		datastore->data = traced;
+		AST_LIST_HEAD_INIT_NOLOCK(&traced->trace);
+		ast_channel_datastore_add(chan, datastore);
+	}
+	traced->enabled = 1;
+	ast_channel_update_trace(chan, traced);
+	return 0;
+}
+
 /*! \brief Hangup a channel */
 int ast_hangup(struct ast_channel *chan)
 {
Index: main/cli.c
===================================================================
--- main/cli.c	(revision 94934)
+++ main/cli.c	(working copy)
@@ -979,6 +979,8 @@
 {
 	struct ast_channel *c=NULL;
 	struct timeval now;
+	struct ast_datastore *store;
+	struct ast_chan_trace_data *traced;
 	struct ast_str *out = ast_str_alloca(2048);
 	char cdrtime[256];
 	char nf[256], wf[256], rf[256];
@@ -1068,7 +1070,11 @@
 		ast_cli(a->fd,"      Variables:\n%s\n", out->str);
 	if (c->cdr && ast_cdr_serialize_variables(c->cdr, &out, '=', '\n', 1))
 		ast_cli(a->fd,"  CDR Variables:\n%s\n", out->str);
-	
+	store = ast_channel_datastore_find(c, &ast_chan_trace_datastore_info, NULL);
+	traced = store ? store->data : NULL;
+	ast_cli(a->fd, "  Context Trace: %s\n", traced && traced->enabled ? "Enabled" : "Disabled");
+	if (traced && traced->enabled && pbx_builtin_serialize_trace(c, &out, traced))
+		ast_cli(a->fd, "          Trace:\n%s\n", out->str);
 	ast_channel_unlock(c);
 	return CLI_SUCCESS;
 }
Index: main/pbx.c
===================================================================
--- main/pbx.c	(revision 94934)
+++ main/pbx.c	(working copy)
@@ -2612,6 +2612,8 @@
 {
 	struct ast_exten *e;
 	struct ast_app *app;
+	struct ast_datastore *datastore;
+	struct ast_chan_trace_data *traced;
 	int res;
 	struct pbx_find_info q = { .stacklen = 0 }; /* the rest is reset in pbx_find_extension */
 	char passdata[EXT_DATA_SIZE];
@@ -2648,6 +2650,10 @@
 				ast_copy_string(c->exten, exten, sizeof(c->exten));
 			c->priority = priority;
 			pbx_substitute_variables(passdata, sizeof(passdata), c, e);
+			datastore = ast_channel_datastore_find(c, &ast_chan_trace_datastore_info, NULL);
+			traced = datastore ? datastore->data : NULL;
+			if (traced && traced->enabled)
+				ast_channel_update_trace(c, traced);
 			ast_debug(1, "Launching '%s'\n", app->name);
 			if (VERBOSITY_ATLEAST(3)) {
 				char tmp[80], tmp2[80], tmp3[EXT_DATA_SIZE];
@@ -7116,6 +7122,37 @@
 	return total;
 }
 
+int pbx_builtin_serialize_trace(struct ast_channel *chan, struct ast_str **buf, struct ast_chan_trace_data *traced)
+{
+	int total = 0;
+	struct ast_chan_trace *trace;
+	struct ast_datastore *store;
+
+	if (!chan)
+		return 0;
+	ast_channel_lock(chan);
+	if (!traced) {
+		store = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
+		if (!store) {
+			ast_log(LOG_WARNING, "No trace to serialize!\n");
+			ast_channel_unlock(chan);
+			return total;
+		}
+		traced = store->data;
+	}
+	(*buf)->used = 0;
+	(*buf)->str[0] = '\0';
+	AST_LIST_TRAVERSE(&traced->trace, trace, entry) {
+		if (ast_str_append(buf, 0, "[%d] => %s, %s, %d\n", total, trace->context, trace->exten, trace->priority) < 0) {
+			ast_log(LOG_ERROR, "Data Buffer Size Exceeded!\n");
+			break;
+		}
+		total++;
+	}
+	ast_channel_unlock(chan);
+	return total;
+}
+
 const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name)
 {
 	struct ast_var_t *variables;