diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index 6870e676bae5ab1376fb3364291f57995bb9fee1..2f5daae76833104f5a5688226566dacf56a0d6b8 100644
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -10112,7 +10112,9 @@ static void *analog_ss_thread(void *data)
 				 * emulation.  The DTMF digits can come so fast that emulation
 				 * can drop some of them.
 				 */
+				ast_channel_lock(chan);
 				ast_set_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY);
+				ast_channel_unlock(chan);
 				off_ms = 4000;/* This is a typical OFF time between rings. */
 				for (;;) {
 					struct ast_frame *f;
@@ -10145,7 +10147,9 @@ static void *analog_ss_thread(void *data)
 						ast_channel_state(chan) == AST_STATE_RINGING)
 						break; /* Got ring */
 				}
+				ast_channel_lock(chan);
 				ast_clear_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY);
+				ast_channel_unlock(chan);
 				dtmfbuf[k] = '\0';
 				dahdi_setlinear(p->subs[idx].dfd, p->subs[idx].linear);
 				/* Got cid and ring. */
diff --git a/channels/sig_analog.c b/channels/sig_analog.c
index 467d548e436da6fb08b3d73c6cd24524ac983a8e..ea0c31d8024d0ce4d6d551a25360d14ba1109c3d 100644
--- a/channels/sig_analog.c
+++ b/channels/sig_analog.c
@@ -2403,7 +2403,9 @@ static void *__analog_ss_thread(void *data)
 				 * emulation.  The DTMF digits can come so fast that emulation
 				 * can drop some of them.
 				 */
+				ast_channel_lock(chan);
 				ast_set_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY);
+				ast_channel_unlock(chan);
 				timeout_ms = 4000;/* This is a typical OFF time between rings. */
 				for (;;) {
 					struct ast_frame *f;
@@ -2438,7 +2440,9 @@ static void *__analog_ss_thread(void *data)
 						break; /* Got ring */
 					}
 				}
+				ast_channel_lock(chan);
 				ast_clear_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY);
+				ast_channel_unlock(chan);
 				dtmfbuf[k] = '\0';
 
 				analog_set_linear_mode(p, idx, oldlinearity);
diff --git a/main/channel.c b/main/channel.c
index a5cc4e7e9fcedcdeca55ea07a998bd765e14f61b..c9a655294d2aae7343e931f5272fb62ef761a1d8 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -6032,7 +6032,9 @@ struct ast_channel *__ast_request_and_dial(const char *type, struct ast_format_c
 	 */
 	ast_set_callerid(chan, cid_num, cid_name, cid_num);
 
+	ast_channel_lock(chan);
 	ast_set_flag(ast_channel_flags(chan), AST_FLAG_ORIGINATED);
+	ast_channel_unlock(chan);
 	ast_party_connected_line_set_init(&connected, ast_channel_connected(chan));
 	if (cid_num) {
 		connected.id.number.valid = 1;