uart4 中断接收 ，轮循发送出现UART_WaitOnFlagUntilTimeout

stm32F103vet rt-thread nano 使用串口uart4中断接收，轮询发送，出现UART_WaitOnFlagUntilTimeout错误
/
GPIO_InitStruct.Pin = GPIO_PIN_10;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
GPIO_InitStruct.Pin = GPIO_PIN_11;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_PULLUP;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
/ UART4 interrupt Init */
HAL_NVIC_SetPriority(UART4_IRQn, 5, 0);
HAL_NVIC_EnableIRQ(UART4_IRQn);

2006 - 2019 Copyright by rt-thread team
msh >00000101 /I RN8302B take mb_send_token_mutex
00000102 /I RN8302B release mb_send_sem
00000102 /I mb get mb_send_sem
00000103 /I RS485 TX
00000114 /I mb .
00000124 /I mb .
psr: 0x21000000
r00: 0x000000b7
r01: 0x0000350c
r02: 0x00000001
r03: 0x000000f8
r04: 0x20010000
r05: 0x0000005e
r06: 0x08007b7f
r07: 0x08007c7f
r08: 0x00000001
r09: 0x000001f4
r10: 0x00000002
r11: 0x2000350e
r12: 0x08007860
lr: 0x080024db
pc: 0x08000894
hard fault on thread: mb_send
thread pri status sp stack size max used left tick error

check_us 16 ready 0x0000005c 0x00000280 14% 0x00000014 -02
rn8302b 16 suspend 0x0000005c 0x00000400 08% 0x00000014 000
AT24CM01 16 suspend 0x0000005c 0x00000400 08% 0x00000014 000
w5500 16 suspend 0x00000084 0x00000400 19% 0x00000014 000
mb_send 16 ready 0x0000006c 0x00000400 36% 0x00000001 000
vol_curr 16 suspend 0x00000074 0x00000200 36% 0x00000013 000
run_stat 16 suspend 0x0000005c 0x00000200 17% 0x00000014 000
key_entr 16 ready 0x0000005c 0x00000200 17% 0x00000014 -02
tshell 21 ready 0x0000006c 0x00000400 10% 0x0000000a -02
tidle 31 ready 0x00000040 0x00000080 62% 0x00000008 000
bus fault:
SCB_CFSR_BFSR:0x82 PRECISERR SCB->BFAR:20010000