From c983aee38abeb528fcda8e3ac8b0ed0c3dd6e2c7 Mon Sep 17 00:00:00 2001
From: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
Date: Tue, 29 Aug 2023 18:43:49 +0800
Subject: [PATCH] driver/serial: fix race condition about calling rxflowcontrol
 in mutli thread

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
---
 drivers/serial/uart_rpmsg.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/serial/uart_rpmsg.c b/drivers/serial/uart_rpmsg.c
index 7cc1587db7..97c7dd3ef3 100644
--- a/drivers/serial/uart_rpmsg.c
+++ b/drivers/serial/uart_rpmsg.c
@@ -161,6 +161,7 @@ static bool uart_rpmsg_rxflowcontrol(FAR struct uart_dev_s *dev,
   FAR struct uart_rpmsg_priv_s *priv = dev->priv;
   FAR struct uart_rpmsg_wakeup_s msg;
 
+  nxmutex_lock(&priv->lock);
   if (!upper && upper != priv->last_upper)
     {
       memset(&msg, 0, sizeof(msg));
@@ -173,6 +174,7 @@ static bool uart_rpmsg_rxflowcontrol(FAR struct uart_dev_s *dev,
     }
 
   priv->last_upper = upper;
+  nxmutex_unlock(&priv->lock);
   return false;
 }