The issues reported in this bug are reproducible on an AWS c6g.2xlarge instance.

The test packages with the backported patch to disable LTO addressed the issues.

...

$ lsb_release -cs
jammy

$ dpkg --print-architecture
arm64

$ sudo dmesg | grep DMI:
[    0.033370] DMI: Amazon EC2 c6g.2xlarge/, BIOS 1.0 11/1/2018


Test 1) riscv64 on arm64, additional bits (comment #4)

	sudo apt install --yes --no-install-recommends qemu-system-riscv64

	wget https://github.com/carlosedp/riscv-bringup/releases/download/v1.0/UbuntuFocal-riscv64-QemuVM.tar.gz

	tar xzf UbuntuFocal-riscv64-QemuVM.tar.gz
	./run_riscvVM.sh
	<... wait ...>
	[  OK  ] Reached target Local File Systems.
		 Starting udev Kernel Device Manager...
	qemu-system-riscv64: ../../block/aio_task.c:64: aio_task_pool_wait_one: Assertion `qemu_coroutine_self() == pool->main_co' failed.
	./run_riscvVM.sh: line 31:  2572 Aborted                 (core dumped) qemu-system-riscv64 -machine virt -nographic -smp 4 -m 4G -bios fw_payload.bin -device virtio-blk-device,drive=hd0 -object rng-random,filename=/dev/urandom,id=rng0 -device virtio-rng-device,rng=rng0 -drive file=riscv64-UbuntuFocal-qemu.qcow2,format=qcow2,id=hd0 -device virtio-net-device,netdev=usernet -netdev user,id=usernet,$ports

	(fails 5/5 times)

Test 2) riscv64 on arm64, ubuntu cloud image (based on comment #4)

	wget https://cloud-images.ubuntu.com/jammy/current/jammy-server-cloudimg-riscv64.img

	sudo modprobe nbd
	sudo qemu-nbd -c /dev/nbd0 --read-only jammy-server-cloudimg-riscv64.img
	sudo mount /dev/nbd0p1 /mnt -o ro

	sudo cp /mnt/boot/vmlinuz-* /mnt/boot/initrd.img-* .
	sudo chown $USER vmlinuz-* initrd.img-*

	sudo umount /mnt
	sudo qemu-nbd -d /dev/nbd0

	qemu-system-riscv64 \
	  -machine virt -nographic \
	  -smp 4 -m 4G \
	  -bios default \
	  -kernel vmlinuz-* -initrd initrd.img-* \
	  -append 'root=/dev/vda1 ro console=ttyS0' \
	  -device virtio-blk-device,drive=drive0 \
	  -drive file=jammy-server-cloudimg-riscv64.img,format=qcow2,id=drive0

	<... wait ~30-60 seconds ...>

	[   36.089758] systemd[1]: Starting Load Kernel Module fuse...
		 Starting Load Kernel Module fuse...
	[   36.134443] systemd[1]: Starting Load Kernel Module pstore_blk...
		 Starting Load Kernel Module pstore_blk...
	qemu-system-riscv64: GLib: g_source_ref: assertion 'source != NULL' failed
	Segmentation fault (core dumped)

	[fails 5/5 times]
	
Test 3) arm64 on arm64, ubuntu cloud image
  
	wget https://cloud-images.ubuntu.com/jammy/current/jammy-server-cloudimg-arm64.img

	sudo apt install --yes --no-install-recommends qemu-system-arm qemu-efi-aarch64 ipxe-qemu

	cp /usr/share/AAVMF/AAVMF_CODE.fd flash0.img
	cp /usr/share/AAVMF/AAVMF_VARS.fd flash1.img

	qemu-system-aarch64 \
	  -machine virt -nographic \
	  -smp 4 -m 4G \
	  -cpu cortex-a57 \
	  -pflash flash0.img -pflash flash1.img \
	  -drive file=jammy-server-cloudimg-arm64.img,format=qcow2,id=drive0,if=none \
	  -device virtio-blk-device,drive=drive0
	...

	BdsDxe: failed to load Boot0001 "UEFI Misc Device" from VenHw(93E34C7E-B50E-11DF-9223-2443DFD72085,00): Not Found
	qemu-system-aarch64: GLib: g_source_ref: assertion 'source != NULL' failed
	Segmentation fault (core dumped)

	[fails 5/5 times]


Test packages with LTO disabled on non-amd64:

amd64 build log:

	../../configure ... --extra-cflags="-g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. 
		-flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects
		-fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2"


arm64 build log:

	../../configure ... --extra-cflags="-g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. 
		-fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2" ...


sudo add-apt-repository -y ppa:mfo/lp1921664
sudo apt install -y qemu-system-misc qemu-system-arm

Test 1)

	./run_riscvVM.sh
	...
	Ubuntu 20.04 LTS Ubuntu-riscv64 ttyS0

	Ubuntu-riscv64 login:

	(3/3 times)


Test 2)

	qemu-system-riscv64 \
	...
	[   25.509053] systemd[1]: Detected architecture riscv64.
	...
	Ubuntu 22.04.2 LTS ubuntu ttyS0

	ubuntu login:

	(3/3 times)

Test 3)

	qemu-system-aarch64 \
	...
	[   41.020286] systemd[1]: Detected architecture arm64.
	...
	[   60.178904] EXT4-fs (vda1): re-mounted. Opts: discard,errors=remount-ro. Quota mode: none.
	< waaaaait >
	
	Ubuntu 22.04.2 LTS ubuntu ttyAMA0

	ubuntu login: