switch_root to real rootfs

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I use `buildroot of ariane-sdk` build image,
and i want to mount `rootfs.tar.xz of lowrsic` as real rootfs.
i modify init script of initramfs:
it will switch to real rootfs by `switch_root`.

During the linux boot process on Ariane:
`[ 27.512532] mmcblk0: mmc0:0000 SS04G 3.69 GiB`
`[ 28.270961] mmcblk0: p1 p2`
`Mounting SD root`
`[ 34.961062] random: fast init done`
`[ 39.051177] EXT4-fs (mmcblk0p2): recovery complete`
`[ 39.691713] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)`
`Mounting proc`
`Mounting sysfs`
`Mounting devtmpfs`
`Mounting devpts`
`Mounting tmpfs`
`Executing switch_root for mmc`
`INIT: version 2.93 booting`
`[ 93.129442] random: crng init done`
`[ 93.129442] random: crng init done`
`[info] Using makefile-style concurrent boot in runlevel S.`
`[info] Setting the system clock.`
`hwclock: Cannot access the Hardware Clock via any known method.`
`hwclock: Use the --verbose option to see the details of our search for an access method.`
`[warn] Unable to set System Clock to: Thu Jan 1 00:02:56 UTC 1970 ... (warning).`
`[ ok ] Activating swap...done.`
`[ 197.397739] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)`
`[ 197.397739] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)`
`[warn] Creating compatibility symlink from /etc/mtab to /proc/mounts. ... (warning).`
`[....] Checking file systems...fsck from util-linux 2.33.1`
`done.`
`[ ok ] Cleaning up temporary files... /tmp.`
`[ ok ] Mounting local filesystems...done.`
`[ ok ] Activating swapfile swap...done.`
`[ ok ] Cleaning up temporary files....`
`[ ok ] Starting Setting kernel variables: sysctl.`
`[....] Configuring network interfaces...Internet Systems Consortium DHCP Client 4.4.1`
`Copyright 2004-2018 Internet Systems Consortium.`
`All rights reserved.`
`For info, please visit https://www.isc.org/software/dhcp/`

`[ 430.874833] Open device, request interrupt 3`
`[ 430.874833] Open device, request interrupt 3`
`Listening on LPF/eth0/23:01:00:89:07:02`
`Sending on LPF/eth0/23:01:00:89:07:02`
`Sending on Socket/fallback`
`Created duid "\000\001\000\001\307\222\276/#\001\000\211\007\002".`
`DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6`
`DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 11`
`DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 17`
`DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 17`
`DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8`
`DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 2`
`No DHCPOFFERS received.`
`No working leases in persistent database - sleeping.`
`done.`
`[ ok ] Starting RPC port mapper daemon: rpcbind.`
`[ ok ] Starting NFS common utilities: statd idmapd.`
`[ ok ] Cleaning up temporary files....`
`INIT: Entering runlevel: 2`

It will stuck at `sbin/int` process,
sometime at `INIT: Entering runlevel: 2`,
or sometime at `[ ok ] Activating swapfile swap...done.`
I don't know why.

If I change `switch_root /mnt /sbin/int` to `chroot /mnt`,
during the linux boot process on Ariane:
`Executing chroot for mmc`
`bash: cannot set terminal process group (-1): Inappropriate ioctl for device`
`bash: no job control in this shell`
`[ 89.290585] random: crng init done`
`[ 89.290585] random: crng init done`
`root@ariane-fpga:/#`

It looks successful, except `bash: cannot set terminal process group (-1): Inappropriate ioctl for device`
But I still want to use `switch_root`,
because it will delete all content of old rootfs(initramfs).

Can you help me?
Thanks You.

Start with the modified init script shown in the issue and compare the switch_root and chroot entry points, using the boot log to locate where startup stops. Done means explaining why switch_root stalls intermittently and establishing a reliable boot transition that removes the initramfs.

Written by the indexing model from the issue text.