Bug#977645: 5.10.1 Debian kernel does not boot on raspi 4 with ext4 rootfs and sdcard

[Ryutaroh Matsumoto <ryutaroh@ict.e.titech.ac.jp>]

Package: linux-image-5.10.0-trunk-arm64-unsigned
Version: 5.10.1-1~exp1
Severity: grave
Justification: renders package unusable

Dear Debian kernel maintainers,

Debian kernel 5.10.1 in experimental does not boot on my raspberry pi 4.
I tried to boot it from an SD card with ext4 root partition.
Partitioining is msdos (not gpt).

I was always able to boot it in the same configuration,
when I used my compiled vanilla 5.10.1 or "git clone"'ning from salsa.debian.

When I use vanilla or salsa.debian.org 5.10.1, booting ALWAYS fails
if rootfs is btrfs.

Photo of boot console is found at
https://photos.app.goo.gl/A755wZKvqneX1WvY6

We observe that booting fails at btrfs.
To me, 5.10.1 btrfs looks very suspicious...

I will see if what will happen with x86_64 with btrfs rootfs...

Best regards, Ryutaroh Matsumoto