2024-03-10 08:29 PM - last edited on 2024-04-30 04:20 AM by Amel NASRI
I am working on an STM32f767 project with LWIP and MQTT. Everything seemed to work for a while but eventually, I received the following assert: "pbuf_free: p->ref > 0..." which caused it to crash sometimes; but sometimes it will continue to work without any issue. Has anyone had a similar issue?
According to LWIP_IAP example, memory location 0x20048000 is labeled as ethernet rx buffer location; however, I could not find where this location is linked to the ethernet rx buffer. for example, 0x2007C000 memory location in the linker file for RxDescripSection & TxDecripSection. And does the size of the MPU region have to be equal to or greater than MEM_SIZE defined in opt.h?
My settings:
LinkerScript.ld
Memory_B1(xrw) : ORIGIN = 0x2004C000, LENGTH = 0xA0
Memory_B2(xrw) : ORIGIN = 0x2004C0A0, LENGTH = 0xA0
.RxDecripSection (NOLOAD) : { *(.RxDescripSection) } >Memory_B1
.TxDecripSection (NOLOAD) : { *(.DMATxDscrTab_section) } >Memory_B2
.ARM.attributes 0 : { *(.ARM.attributes) }
main.c
/* Configure the MPU as Normal Non Cacheable for Ethernet Buffers in the SRAM2 */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x20048000;
MPU_InitStruct.Size = MPU_REGION_SIZE_16KB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER1;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL1;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Configure the MPU as Device for Ethernet Descriptors in the SRAM2 */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x2004C000;
MPU_InitStruct.Size = MPU_REGION_SIZE_1KB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER2;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE
HAL_MPU_ConfigRegion(&MPU_InitStruct);
Solved! Go to Solution.
2024-07-05 08:02 AM
Hello @cleonb322 ,
based on the example LwIP_HTTP_Server_Netconn_RTOS your MPU configuration should be as follows as you are using an STM32F767 check RM0410
static void MPU_Config(void)
{
MPU_Region_InitTypeDef MPU_InitStruct;
/* Disable the MPU */
HAL_MPU_Disable();
/* Configure the MPU as Strongly ordered for not defined regions */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x00;
MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER0;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x87;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Configure the MPU as Normal Non Cacheable for Ethernet Buffers in the SRAM2 */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x20078000;
MPU_InitStruct.Size = MPU_REGION_SIZE_16KB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER1;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL1;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Configure the MPU as Device for Ethernet Descriptors in the SRAM2 */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x2007C000;
MPU_InitStruct.Size = MPU_REGION_SIZE_1KB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER2;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Enable the MPU */
HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
}
The MPU configuration you are using is valid for stm32f75xx and stm32f74xx check RM0385
Regards
2024-07-05 08:02 AM
Hello @cleonb322 ,
based on the example LwIP_HTTP_Server_Netconn_RTOS your MPU configuration should be as follows as you are using an STM32F767 check RM0410
static void MPU_Config(void)
{
MPU_Region_InitTypeDef MPU_InitStruct;
/* Disable the MPU */
HAL_MPU_Disable();
/* Configure the MPU as Strongly ordered for not defined regions */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x00;
MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER0;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x87;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Configure the MPU as Normal Non Cacheable for Ethernet Buffers in the SRAM2 */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x20078000;
MPU_InitStruct.Size = MPU_REGION_SIZE_16KB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER1;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL1;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Configure the MPU as Device for Ethernet Descriptors in the SRAM2 */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x2007C000;
MPU_InitStruct.Size = MPU_REGION_SIZE_1KB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER2;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Enable the MPU */
HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
}
The MPU configuration you are using is valid for stm32f75xx and stm32f74xx check RM0385
Regards
2024-10-22 06:09 AM
Thank you for the help. it no longer crashes but I still receive "pbuf_free: p->ref > 0" occasionally on the debug console. Do you know of other potential causes of the issue?
2024-10-22 06:21 AM
Hello @cleonb322 ,
This most probably related to LWIP memory management and since it is not systematic maybe it can be a problem of alignment or luck of allocated memory.
As far as I recall there are two routes to manage memory in LWIP either dynamically or statically and this could be adjusted by the user.
have a look at sections 3.2 and 4 of UM1713 .
Regards
2024-10-22 04:05 PM
I forget to update this: #define LWIP_RAM_HEAP_POINTER (0x20078000) in iwapopts.h
2024-10-26 10:14 PM
I tried to enable TLS, but it failed malloc because MBEDTLS_SSL_IN_BUFFER_LEN size is 16717 and the available memory is 16K (16384) for SRAM2. according to TLS standards, I should not change the size of MBEDTLS_SSL_IN_BUFFER_LEN. what are my options? I have an external RAM on the device for display buffer with plenty of space available. is it possible to use the external RAM starting at memory location 0xC0000000?