On Fri, Aug 19, 2016 at 04:17:22PM +0200, Andre Schmidt wrote:

make ARCH=x86_64 allnoconfig
make all
qemu-system-x86_64 -kernel arch/x86/boot/bzImage

Those commands above used to be enough, but now the produced kernel doesn't print any messages on the qemu screen.

With some trial-and-error i was able to track down this commit
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/init/Kconfig?id=5d2acfc7b974bbd3858b4dd3f2cdc6362dd8843a
and if i add CONFIG_EMBEDDED=n to my KCONFIG_ALLCONFIG file, i can see kernel errors again.
(CONFIG_EMBEDDED=n sounds pretty generic and doesn't feel right)

Can you reproduce this?

yes

ps. i'm aware of defconfig, but i would like to experiment/learn from bottom-up, rather than top-down.

I've done the same and would have expected the the previous behavior,
too.