STM32H743ZI - Bug in ethernetif.c ?

Invalidating all cache will damage other unrelated data. Cleaning all cache can be safe, but is much slower anyway. Proper way is this:

for(q = p; q != NULL; q = q->next)
{
	...
	SCB_CleanDCache_by_Addr(q->payload, q->len);
	...
}

This must be added to the for loop inside low_level_output().

Thanks for the advice. I changed it like you said and it works, too.

But why do I have to add this line? And why is it not added automaticly by STM32CubeIDE (Version: 1.0.2)  ?

My MPU settings and linker command file are copied from "LwIP_HTTP_Server_Netconn_RTOS" example in "STM32Cube_FW_H7_V1.5.0".

The MPU settings look as follows:

void MPU_Config(void)
{
 MPU_Region_InitTypeDef MPU_InitStruct = {0};
 
 /* Disables the MPU */
 HAL_MPU_Disable();
 /** Initializes and configures the Region and the memory to be protected 
 */
 MPU_InitStruct.Enable = MPU_REGION_ENABLE;
 MPU_InitStruct.Number = MPU_REGION_NUMBER0;
 MPU_InitStruct.BaseAddress = 0x30040000;
 MPU_InitStruct.Size = MPU_REGION_SIZE_256B;
 MPU_InitStruct.SubRegionDisable = 0x0;
 MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
 MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
 MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
 MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
 MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
 MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE;
 
 HAL_MPU_ConfigRegion(&MPU_InitStruct);
 /** Initializes and configures the Region and the memory to be protected 
 */
 MPU_InitStruct.Enable = MPU_REGION_ENABLE;
 MPU_InitStruct.Number = MPU_REGION_NUMBER1;
 MPU_InitStruct.BaseAddress = 0x30044000;
 MPU_InitStruct.Size = MPU_REGION_SIZE_16KB;
 MPU_InitStruct.SubRegionDisable = 0x0;
 MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL1;
 MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
 MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
 MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
 MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
 MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
 
 HAL_MPU_ConfigRegion(&MPU_InitStruct);
 /* Enables the MPU */
 HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
 
}

Amd this is my Linker File:

/* Entry Point */
ENTRY(Reset_Handler)
 
/* Highest address of the user mode stack */
_estack = 0x24080000; /* end of RAM */
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0x1000; /* required amount of heap */
_Min_Stack_Size = 0x1000; /* required amount of stack */
 
/* Specify the memory areas */
MEMORY
{
DTCMRAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
RAM_D1 (xrw) : ORIGIN = 0x24000000, LENGTH = 512K
RAM_D2 (xrw) : ORIGIN = 0x30000000, LENGTH = 288K
RAM_D3 (xrw) : ORIGIN = 0x38000000, LENGTH = 64K
ITCMRAM (xrw) : ORIGIN = 0x00000000, LENGTH = 64K
FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 2048K
}
 
/* Define output sections */
SECTIONS
{
 /* The startup code goes first into FLASH */
 .isr_vector :
 {
 . = ALIGN(4);
 KEEP(*(.isr_vector)) /* Startup code */
 . = ALIGN(4);
 } >FLASH
 
 /* The program code and other data goes into FLASH */
 .text :
 {
 . = ALIGN(4);
 *(.text) /* .text sections (code) */
 *(.text*) /* .text* sections (code) */
 *(.glue_7) /* glue arm to thumb code */
 *(.glue_7t) /* glue thumb to arm code */
 *(.eh_frame)
 
 KEEP (*(.init))
 KEEP (*(.fini))
 
 . = ALIGN(4);
 _etext = .; /* define a global symbols at end of code */
 } >FLASH
 
 /* Constant data goes into FLASH */
 .rodata :
 {
 . = ALIGN(4);
 *(.rodata) /* .rodata sections (constants, strings, etc.) */
 *(.rodata*) /* .rodata* sections (constants, strings, etc.) */
 . = ALIGN(4);
 } >FLASH
 
 .ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
 .ARM : {
 __exidx_start = .;
 *(.ARM.exidx*)
 __exidx_end = .;
 } >FLASH
 
 .preinit_array :
 {
 PROVIDE_HIDDEN (__preinit_array_start = .);
 KEEP (*(.preinit_array*))
 PROVIDE_HIDDEN (__preinit_array_end = .);
 } >FLASH
 .init_array :
 {
 PROVIDE_HIDDEN (__init_array_start = .);
 KEEP (*(SORT(.init_array.*)))
 KEEP (*(.init_array*))
 PROVIDE_HIDDEN (__init_array_end = .);
 } >FLASH
 .fini_array :
 {
 PROVIDE_HIDDEN (__fini_array_start = .);
 KEEP (*(SORT(.fini_array.*)))
 KEEP (*(.fini_array*))
 PROVIDE_HIDDEN (__fini_array_end = .);
 } >FLASH
 
 /* used by the startup to initialize data */
 _sidata = LOADADDR(.data);
 
 /* Initialized data sections goes into RAM, load LMA copy after code */
 .data : 
 {
 . = ALIGN(4);
 _sdata = .; /* create a global symbol at data start */
 *(.data) /* .data sections */
 *(.data*) /* .data* sections */
 
 . = ALIGN(4);
 _edata = .; /* define a global symbol at data end */
 } >RAM_D1 AT> FLASH
 
 
 /* Uninitialized data section */
 . = ALIGN(4);
 .bss :
 {
 /* This is used by the startup in order to initialize the .bss secion */
 _sbss = .; /* define a global symbol at bss start */
 __bss_start__ = _sbss;
 *(.bss)
 *(.bss*)
 *(COMMON)
 
 . = ALIGN(4);
 _ebss = .; /* define a global symbol at bss end */
 __bss_end__ = _ebss;
 } >RAM_D1
 
 /* User_heap_stack section, used to check that there is enough RAM left */
 ._user_heap_stack :
 {
 . = ALIGN(8);
 PROVIDE ( end = . );
 PROVIDE ( _end = . );
 . = . + _Min_Heap_Size;
 . = . + _Min_Stack_Size;
 . = ALIGN(8);
 } >RAM_D1
 
 
 .lwip_sec (NOLOAD) : {
 . = ABSOLUTE(0x30040000);
 *(.RxDecripSection) 
 
 . = ABSOLUTE(0x30040060);
 *(.TxDecripSection)
 
 . = ABSOLUTE(0x30040200);
 *(.RxArraySection) 
 } >RAM_D2 AT> FLASH
 
 /* Remove information from the standard libraries */
 /DISCARD/ :
 {
 libc.a ( * )
 libm.a ( * )
 libgcc.a ( * )
 }
 
 .ARM.attributes 0 : { *(.ARM.attributes) }
}