NRF_LOG causes device reset if RTT viewer not connected

[kubazdz]

When RTT viewer is not connected, the buffer will eventually overflow and it causes device hanging and being reset by wdt eventually. When I connect to the RTT viewer before wdt resets the device, all logs will flush and the device will continue to work correctly. In the application I call NRF_LOG_INFO, NRF_LOG_HEXDUMP_INFO and NRF_LOG_FLUSH(). 

Here are my sdk_configs:

#define NRF_LOG_BACKEND_RTT_ENABLED 1
#define NRF_LOG_BACKEND_RTT_TEMP_BUFFER_SIZE 64
#define NRF_LOG_BACKEND_RTT_TX_RETRY_DELAY_MS 1
#define NRF_LOG_BACKEND_RTT_TX_RETRY_CNT 3
#define NRF_LOG_ENABLED 1
#define NRF_LOG_MSGPOOL_ELEMENT_SIZE 20
#define NRF_LOG_MSGPOOL_ELEMENT_COUNT 8
#define NRF_LOG_ALLOW_OVERFLOW 1
#define NRF_LOG_BUFSIZE 1024
#define NRF_LOG_CLI_CMDS 0
#define NRF_LOG_DEFAULT_LEVEL 3
#define NRF_LOG_DEFERRED 1
#define NRF_LOG_FILTERS_ENABLED 0
#define NRF_LOG_NON_DEFFERED_CRITICAL_REGION_ENABLED 0
#define NRF_LOG_STR_PUSH_BUFFER_SIZE 128

[Susheel Nuguru]

Assuming that you are using nRF5SDKv 17.1.0, you can put the breakpoints at the below places and run your application in the debugger.

nRF5_SDK_17.1.0_ddde560/components/boards/boards.c(120):NVIC_SystemReset();
nRF5_SDK_17.1.0_ddde560/components/libraries/hardfault/hardfault_implementation.c(59):NVIC_SystemReset();
nRF5_SDK_17.1.0_ddde560/components/libraries/pwr_mgmt/nrf_pwr_mgmt.c(409):NVIC_SystemReset();
nRF5_SDK_17.1.0_ddde560/components/libraries/util/app_error_weak.c(105):NVIC_SystemReset();

When one of them is hit, then we get the context of the error.

I tried to flood the RTT and also used your config and disconnect it from the RTT viewer and I did not see any resets.