diff -urN asterisk-11.2.1.orig/channels/chan_dahdi.c asterisk-11.2.1/channels/chan_dahdi.c
--- asterisk-11.2.1.orig/channels/chan_dahdi.c	2013-01-09 12:43:00.000000000 -0800
+++ asterisk-11.2.1/channels/chan_dahdi.c	2013-03-25 13:50:01.961196138 -0700
@@ -2163,18 +2163,16 @@
 					ast_channel_unlock(ast);
 					if (ast_exists_extension(ast, target_context, "fax", 1,
 						S_COR(ast_channel_caller(ast)->id.number.valid, ast_channel_caller(ast)->id.number.str, NULL))) {
-						ast_channel_lock(ast);
-						ast_mutex_lock(&p->lock);
 						ast_verb(3, "Redirecting %s to fax extension\n", ast_channel_name(ast));
 						/* Save the DID/DNIS when we transfer the fax call to a "fax" extension */
 						pbx_builtin_setvar_helper(ast, "FAXEXTEN", ast_channel_exten(ast));
 						if (ast_async_goto(ast, target_context, "fax", 1))
 							ast_log(LOG_WARNING, "Failed to async goto '%s' into fax of '%s'\n", ast_channel_name(ast), target_context);
 					} else {
-						ast_channel_lock(ast);
-						ast_mutex_lock(&p->lock);
 						ast_log(LOG_NOTICE, "Fax detected, but no fax extension\n");
 					}
+					ast_channel_lock(ast);
+					ast_mutex_lock(&p->lock);
 				} else {
 					ast_debug(1, "Already in a fax extension, not redirecting\n");
 				}
@@ -7980,18 +7978,16 @@
 					ast_channel_unlock(ast);
 					if (ast_exists_extension(ast, target_context, "fax", 1,
 						S_COR(ast_channel_caller(ast)->id.number.valid, ast_channel_caller(ast)->id.number.str, NULL))) {
-						ast_channel_lock(ast);
-						ast_mutex_lock(&p->lock);
 						ast_verb(3, "Redirecting %s to fax extension\n", ast_channel_name(ast));
 						/* Save the DID/DNIS when we transfer the fax call to a "fax" extension */
 						pbx_builtin_setvar_helper(ast, "FAXEXTEN", ast_channel_exten(ast));
 						if (ast_async_goto(ast, target_context, "fax", 1))
 							ast_log(LOG_WARNING, "Failed to async goto '%s' into fax of '%s'\n", ast_channel_name(ast), target_context);
 					} else {
-						ast_channel_lock(ast);
-						ast_mutex_lock(&p->lock);
 						ast_log(LOG_NOTICE, "Fax detected, but no fax extension\n");
 					}
+					ast_channel_lock(ast);
+					ast_mutex_lock(&p->lock);
 				} else {
 					ast_debug(1, "Already in a fax extension, not redirecting\n");
 				}
diff -urN asterisk-11.2.1.orig/channels/chan_sip.c asterisk-11.2.1/channels/chan_sip.c
--- asterisk-11.2.1.orig/channels/chan_sip.c	2013-01-09 12:43:00.000000000 -0800
+++ asterisk-11.2.1/channels/chan_sip.c	2013-03-25 14:06:00.740193835 -0700
@@ -8397,8 +8397,6 @@
 			ast_channel_unlock(ast);
 			if (ast_exists_extension(ast, target_context, "fax", 1,
 				S_COR(ast_channel_caller(ast)->id.number.valid, ast_channel_caller(ast)->id.number.str, NULL))) {
-				ast_channel_lock(ast);
-				sip_pvt_lock(p);
 				ast_verb(2, "Redirecting '%s' to fax extension due to CNG detection\n", ast_channel_name(ast));
 				pbx_builtin_setvar_helper(ast, "FAXEXTEN", ast_channel_exten(ast));
 				if (ast_async_goto(ast, target_context, "fax", 1)) {
@@ -8407,10 +8405,10 @@
 				ast_frfree(fr);
 				fr = &ast_null_frame;
 			} else {
-				ast_channel_lock(ast);
-				sip_pvt_lock(p);
 				ast_log(LOG_NOTICE, "FAX CNG detected but no fax extension\n");
 			}
+			ast_channel_lock(ast);
+			sip_pvt_lock(p);
 		}
 	}
 
@@ -10637,6 +10635,7 @@
 						ast_channel_unlock(p->owner);
 						if (ast_exists_extension(p->owner, target_context, "fax", 1,
 							S_COR(ast_channel_caller(p->owner)->id.number.valid, ast_channel_caller(p->owner)->id.number.str, NULL))) {
+							ast_log(LOG_WARNING, "Usage of 'faxdetect=[yes|t38]' setting in sip.conf is not recommended. Please consider Set(FAXOPT(faxdetect)=[yes|t38]) instead.\n");
 							ast_verb(2, "Redirecting '%s' to fax extension due to peer T.38 re-INVITE\n", ast_channel_name(p->owner));
 							pbx_builtin_setvar_helper(p->owner, "FAXEXTEN", ast_channel_exten(p->owner));
 							if (ast_async_goto(p->owner, target_context, "fax", 1)) {
diff -urN asterisk-11.2.1.orig/res/res_fax.c asterisk-11.2.1/res/res_fax.c
--- asterisk-11.2.1.orig/res/res_fax.c	2012-11-08 14:08:58.000000000 -0800
+++ asterisk-11.2.1/res/res_fax.c	2013-03-25 13:57:11.990193578 -0700
@@ -3388,10 +3388,13 @@
 		switch (result) {
 		case 'f':
 		case 't':
+			if (!strcmp(ast_channel_exten(chan), "fax")) {
+				ast_debug(1, "Already in a fax extension, not redirecting\n");
+				break;
+			}
 			ast_channel_unlock(chan);
 			if (ast_exists_extension(chan, target_context, "fax", 1,
 			    S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL))) {
-				ast_channel_lock(chan);
 				ast_verb(2, "Redirecting '%s' to fax extension due to %s detection\n",
 					ast_channel_name(chan), (result == 'f') ? "CNG" : "T38");
 				pbx_builtin_setvar_helper(chan, "FAXEXTEN", ast_channel_exten(chan));
@@ -3401,10 +3404,10 @@
 				ast_frfree(f);
 				f = &ast_null_frame;
 			} else {
-				ast_channel_lock(chan);
 				ast_log(LOG_NOTICE, "FAX %s detected but no fax extension in context (%s)\n",
 					(result == 'f') ? "CNG" : "T38", target_context);
 			}
+			ast_channel_lock(chan);
 		}
 		ast_framehook_detach(chan, details->faxdetect_id);
 		details->faxdetect_id = -1;