diff --git a/drivers/char/diag/diag_mux.c b/drivers/char/diag/diag_mux.c
index 8cc803eef552..8d766e1ae583 100644
--- a/drivers/char/diag/diag_mux.c
+++ b/drivers/char/diag/diag_mux.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -239,6 +239,8 @@ int diag_mux_switch_logging(int *req_mode, int *peripheral_mask)
 		new_mask = ~(*peripheral_mask) & diag_mux->mux_mask;
 		if (new_mask != DIAG_CON_NONE)
 			*req_mode = DIAG_MULTI_MODE;
+		if (new_mask == DIAG_CON_ALL)
+			*req_mode = DIAG_MEMORY_DEVICE_MODE;
 		break;
 	case DIAG_MEMORY_DEVICE_MODE:
 		new_mask = (*peripheral_mask) | diag_mux->mux_mask;
diff --git a/drivers/char/diag/diagchar_core.c b/drivers/char/diag/diagchar_core.c
index 678e3a2b051c..4885412dd014 100644
--- a/drivers/char/diag/diagchar_core.c
+++ b/drivers/char/diag/diagchar_core.c
@@ -1710,19 +1710,20 @@ static int diag_switch_logging(struct diag_logging_mode_param_t *param)
 			return -EINVAL;
 		}
 
+		i = upd - UPD_WLAN;
+
 		if (driver->md_session_map[peripheral] &&
 			(MD_PERIPHERAL_MASK(peripheral) &
-			diag_mux->mux_mask)) {
+			diag_mux->mux_mask) &&
+			!driver->pd_session_clear[i]) {
 			DIAG_LOG(DIAG_DEBUG_USERSPACE,
 			"diag_fr: User PD is already logging onto active peripheral logging\n");
-			i = upd - UPD_WLAN;
 			driver->pd_session_clear[i] = 0;
 			return -EINVAL;
 		}
 		peripheral_mask =
 			diag_translate_mask(param->pd_mask);
 		param->peripheral_mask = peripheral_mask;
-		i = upd - UPD_WLAN;
 		if (!driver->pd_session_clear[i]) {
 			driver->pd_logging_mode[i] = 1;
 			driver->num_pd_session += 1;
diff --git a/drivers/char/diag/diagfwd.c b/drivers/char/diag/diagfwd.c
index f876489e202d..f6027ae96833 100644
--- a/drivers/char/diag/diagfwd.c
+++ b/drivers/char/diag/diagfwd.c
@@ -1003,8 +1003,11 @@ int diag_process_apps_pkt(unsigned char *buf, int len, int pid)
 		} else {
 			mutex_unlock(&driver->md_session_lock);
 			if (MD_PERIPHERAL_MASK(reg_item->proc) &
-				driver->logging_mask)
+				driver->logging_mask) {
+				mutex_unlock(&driver->cmd_reg_mutex);
 				diag_send_error_rsp(buf, len, pid);
+				return write_len;
+			}
 			else
 				write_len = diag_send_data(reg_item, buf, len);
 		}