UART on nrf9160dk

[Jagruti]

Hello,

I am using UART1 to communicate with sensor. It is working fine. I can receive the data. Now I want to modify this data. When I use strcpy() function, it works properly. But when I use functions like strchr(), there is error. I will paste the code and error as well.

To modify the received data from sensor, I am modifying the UART callback function. So is this the reason for the error and what should I do to overcome this problem?

Code:

#include <zephyr.h>
#include <misc/printk.h>
#include <uart.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

static u8_t uart_buf[1024];

void uart_cb(struct device *x)
{
	uart_irq_update(x);
	int data_length = 0;

	if (uart_irq_rx_ready(x)) {
		data_length = uart_fifo_read(x, uart_buf, sizeof(uart_buf));
		uart_buf[data_length] = 0;
	}

	printk("%s", uart_buf);
   //     k_sleep(1000);
        char dest[strlen(uart_buf)];
   //     strncpy(dest,uart_buf,strlen(uart_buf));
        strcpy(dest, uart_buf);
        printk("%s", dest);
        const char ch = ',';
         char *ret;

         ret = strchr(uart_buf, ch);
         printk("%s", ret);

}

void main(void)
{
        
	struct device *uart = device_get_binding("UART_1");

	uart_irq_callback_set(uart, uart_cb);
	uart_irq_rx_enable(uart);
	printk("UART loopback start!\n");
	while (1) {
		k_cpu_idle();
                
	}
}

Output:

UART loopback start!
$Exception occurred in Secure State
***** HARD FAULT *****
  Fault escalation (see below)
***** BUS FAULT *****
  Precise data bus error
  BFAR Address: 0x50008120
***** Hardware exception *****
Current thread ID = 0x200200b0
Faulting instruction address = 0xe608
Fatal fault in ISR! Spinning...