[BUG] PR #15462 breaks the heap on MPFS targets

[jlaitine]

Description / Steps to reproduce the issue

After commit 11d54b3, the mm_foreach (in mm/mm_heap/mm_foreach.c) occasionally gets stuck in busyloop, or asserts if CONFIG_DEBUG_ASSERTIONS=y.

Debugging the issue further, the node->size == 3, and the macro MM_SIZEOF_NODE returns 0 on line "nodesize = MM_SIZEOF_NODE(node);"

The issue is resolved if I configure the CONFIG_MM_DEFAULT_ALIGNMENT=0, which results alignment of 16

On which OS does this issue occur?

[OS: Linux]

What is the version of your OS?

Ubuntu 22.04

NuttX Version

master

Issue Architecture

[Arch: risc-v]

Issue Area

[Area: Memory Management]

Host information

No response

Verification

• I have verified before submitting the report.

[jlaitine]

After reverting the ttyACM PR, mentioned in #16004, I haven't been able to re-produce this issue. So it is possible that this was just due to the kernel heap corruption due to that. I am closing this, as I believe it is a duplicate for that.