--- ../clean/asterisk-1.6.2.16.1/channels/chan_sip.c	2010-12-10 00:10:31.000000000 +0200
+++ channels/chan_sip.c	2011-02-11 09:11:01.000000000 +0200
@@ -7158,10 +7158,8 @@
 
 	/* If we detect a CNG tone and fax detection is enabled then send us off to the fax extension */
 	if (faxdetected && ast_test_flag(&p->flags[1], SIP_PAGE2_FAX_DETECT_CNG)) {
-		ast_channel_lock(ast);
 		if (strcmp(ast->exten, "fax")) {
 			const char *target_context = S_OR(ast->macrocontext, ast->context);
-			ast_channel_unlock(ast);
 			if (ast_exists_extension(ast, target_context, "fax", 1, ast->cid.cid_num)) {
 				ast_verbose(VERBOSE_PREFIX_2 "Redirecting '%s' to fax extension due to CNG detection\n", ast->name);
 				pbx_builtin_setvar_helper(ast, "FAXEXTEN", ast->exten);
@@ -7172,8 +7170,6 @@
 			} else {
 				ast_log(LOG_NOTICE, "FAX CNG detected but no fax extension\n");
                         }
-		} else {
-			ast_channel_unlock(ast);
                 }
         }
 
@@ -18161,7 +18157,9 @@
 			if (ast_test_flag(&p->flags[1], SIP_PAGE2_STATECHANGEQUEUE)) {
 				/* Ready to send the next state we have on queue */
 				ast_clear_flag(&p->flags[1], SIP_PAGE2_STATECHANGEQUEUE);
+				ast_rdlock_contexts();
 				cb_extensionstate((char *)p->context, (char *)p->exten, p->laststate, (void *) p);
+				ast_unlock_contexts();
 			}
 		}
 		break;
@@ -18872,7 +18870,9 @@
 					if (ast_test_flag(&p->flags[1], SIP_PAGE2_STATECHANGEQUEUE)) {
 						/* Ready to send the next state we have on queue */
 						ast_clear_flag(&p->flags[1], SIP_PAGE2_STATECHANGEQUEUE);
+						ast_rdlock_contexts();
 						cb_extensionstate((char *)p->context, (char *)p->exten, p->laststate, (void *) p);
+						ast_unlock_contexts();
 					}
 				}
 			} else if (sipmethod == SIP_BYE) {