Hi!
I have an application running on an STM32F411 with FreeRTOS v10.4.3.
Sometimes the application crashes. It can occur after 10 seconds or 10 minutes, sometimes longer. I have traced the cause of the crash to be an incorrect pxCurrentTCB value during a xTaskIncrementTick() call.
Here are the values in pxCurrentPCB read with Ozone:
Level,Expression,Value,Location,Type
0,pxCurrentTCB,0x20009110,0x20006284,volatile struct tskTaskControlBlock*
1,pxTopOfStack,0xA5A5A5A5,0x20009110,volatile unsigned long*
1,xStateListItem,0x20009114,struct xLIST_ITEM
1,xEventListItem,0x20009128,struct xLIST_ITEM
1,uxPriority,2779096485,0x2000913C,unsigned long
1,pxStack,0xA5A5A5A5,0x20009140,unsigned long*
1,pcTaskName,“\245\245\245\245\245\245\245\245\245\245\245\245\245\245\245\245…”,0x20009144,char[16]
1,uxBasePriority,2779096485,0x20009154,unsigned long
1,uxMutexesHeld,2779096485,0x20009158,unsigned long
1,ulNotifiedValue,0x2000915C,volatile unsigned long[1]
1,ucNotifyState,“\245…”,0x20009160,volatile unsigned char[1]
1,ucStaticallyAllocated,165 (‘¥’),0x20009161,unsigned char
Looking at the uxPriority or pcTaskName I can see that these values are invalid. Because of the invalid value of uxPriority, this line (tasks.c, line 2843):
if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ pxCurrentTCB->uxPriority ] ) ) > ( UBaseType_t ) 1 )
causes a hardfault.
I’ve read several similar topics on this forum, but they don’t seem relevant to me. I have checked my interrupt priorities configuration:
In FreeRTOSConfig.h I have:
#ifdef __NVIC_PRIO_BITS
#define configPRIO_BITS __NVIC_PRIO_BITS
#else
#define configPRIO_BITS 4
#endif
#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY 15
#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY 4
In main(), I call NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_4);.
I have only a few interrupts, and all of them have priority at either 4 or 5.
In these few interrupts, if I call a FreeRTOS-related function I use the FromISR() variant.
What may be interesting is that I only ever catch this crash when the SysTick occurs during a memcpy() call, but it’s possible that I just copy a lot of data 
To be sure, I implemented my own, super-simple memcpy() that just copies data byte-by-byte in a for loop and verified that my code is using it, but it didn’t change a thing.
What am I doing wrong? Thanks in advance.