majerle / lwwdg Goto Github PK

description

• lwwdg_process got a time_curr < last_reload_time, WDG_IS_EXPIRED got a huge negative overflow value and return true, causing unexpected system reset

platform information

• lwwdg version: 1.1.1
• FreeRTOS version V10.3.1, tickless idle enabled, handled by LPTIM-Tick
• MCU: STM32G071

steps to reproduce:

1. setup some tasks, and run lwwdg_process in wdg_task which has a priority equal to idle task
2. set a breakpoint when lwwdg_process set failed = 1
3. run until the breakpoint is triggered

possible cause

• after time_curr = LWWDG_GET_TIME();, scheduler interrupt wdg_task and run other tasks with higher priority, then wdg_reload was called in these tasks. This could will lead to time_curr slightly behind last_reload_time.

possible fix

• in lwwdg_process, move LWWDG_GET_TIME into critical section