FreeRTOS Message Buffer Core to Core Bus-Fault Error

[Flo1989]

Hello,

we are using the freertos_message_buffer from the example provided in the sdk on a imxrt1176 device.

We extended the memory to send and receive blocks with a length of 1024bytes. So our config looks like this:

#define APP_TASK_STACK_SIZE                                (configMINIMAL_STACK_SIZE + 100)
#define APP_READY_EVENT_DATA                               (1U)
#define APP_MESSAGE_BUFFER_EVENT_DATA                      (1U)
#define APP_MAX_MESSAGE_LENGTH							   (0x400U)
#define APP_MESSAGE_BUFFER_SIZE                            (0x800U)
#define APP_SH_MEM_PRIMARY_TO_SECONDARY_MB_OFFSET          (0x0u)
#define APP_SH_MEM_SECONDARY_TO_PRIMARY_MB_OFFSET          (0x4u)
#define APP_SH_MEM_PRIMARY_TO_SECONDARY_MB_STRUCT_OFFSET   (0x50u)
#define APP_SH_MEM_SECONDARY_TO_PRIMARY_MB_STRUCT_OFFSET   (0xA0u)
#define APP_SH_MEM_PRIMARY_TO_SECONDARY_BUF_STORAGE_OFFSET (0x100u)
#define APP_SH_MEM_SECONDARY_TO_PRIMARY_BUF_STORAGE_OFFSET (0x900u)

#define SH_MEM_TOTAL_SIZE (6144U)

It seems the cm7 core tries to notify a task on the cm4 core wich results in a bus-fault error. Normaly the cm7 core should not notify the task, becaouse in the xStreamBuffer struct the xTaskWaitingToSend pointer is NULL.

But if the sbRECEIVE_COMPLETE macro is called the xTaskGenericNotify() fuction is called with the task address from the cm4 task. This results in a BusFault Address Register (BFAR) valid flag.

The rpmsh_sh_mem is located at address 0x202c0000 and looks like this. Here i can see the address of the slave task (0x1FFF6394) which is wrong called from the cm7 in the xSecondaryToPrimaryMessageBufferStruct at address 0x202C0060.

From the call hirarchy the sbRECEIVE_COMPLETE Macro should not call xTaskNotify because the xStreamBuffers xTaskWaitingToReceive is NULL.

Has anyone an idea what is happening here?

Thank you,

Florian

[Flo1989]

Hi Jing,

we are using the message buffers in a bigger software that i can not share with you. The problem occures not immediately. The sofware is running for 10h with much traffic through the message buffer.

I now overwrote the sbRECEIVE_COMPLETE like the sbSEND_COMPLETED macro is overwritten. But i do nothing in the sbRECEIVE_COMPLETED macro function now. With this change the software is running well. But i would like to understand whats the reason for this behaviour.

Thanks,

Florian

[jingpan]

Hi @Flo1989 ,

Sometimes busfault will not happened immediately after the wrong instruction.

Regards,

Jing

[jingpan]

Hi @Flo1989 ,

I modified freertos_message_buffers_cm7 and freertos_message_buffers_cm4 project using your code. But I don't see any problem. What else do you modified?

Regards,

Jing