aarch64 BYE crash: add heap-address diagnostics, rule out gdb debugging on this target

Continued investigating the aarch64 BYE cold-restart exception (FABRIC-2.md
Section I). Added permanent boot diagnostics: kmalloc_heap_base_addr()/
kmalloc_heap_end_addr() now print in print_heap_stats(), confirming the
fault address is provably inside the kmalloc heap (not kernel code, not
firmware). Bumped aarch64 QEMU RAM to 4096MB to test heap-placement
sensitivity (no effect -- heap size is a fixed 2GiB default, independent
of total RAM once "enough" exists).

Three separate live gdb debugging attempts (software breakpoint, hardware
breakpoint on arch_cold_reset, hardware breakpoint on mama_word_bye's
entry) all silently failed to fire despite disassembly-confirmed-correct
addresses and confirmed execution reaching those points. A sanity check
(hbreak on console_println, called thousands of times per boot) also never
fired even 8802 lines into a serial log -- conclusively a gdbstub/QEMU
tooling limitation for this aarch64 target, not a kernel-side finding.
Live single-stepping is not currently viable here; documented so it isn't
re-attempted the same way.

Root cause still open. Full trail in FABRIC-2.md Section I.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

This commit is contained in:

Robert Allan James

2026-08-18 17:06:58 -04:00

co-authored by

Claude Sonnet 5

parent 8d90538801

commit bc31916461

11 changed files with 308066 additions and 32 deletions

									
										Makefile.starkernel
									
		+1
		-1
	
												View File
												
				@@ -815,7 +815,7 @@ else ifeq ($(ARCH),aarch64)

						-chardev socket,id=cserial,path=$$SERIAL_SOCK,server=on,wait=off,logfile=$$LOG \

						-serial chardev:cserial \

						-display $(QEMU_DISPLAY) \

						-m 2048 \

						-m 4096 \

						-no-reboot \

						-d guest_errors; \

					kill $$TAILPID 2>/dev/null; wait $$TAILPID 2>/dev/null || true; \