CentOS - Dec 2016 - Panic on boot with 7.3 kernels when decrypting hard drive

I was excited to update my system to CentOS 7.3/1611 yesterday when
the release announcement came through, but since then I've been
running into some serious kernel issues.

I've been successfully running 7.2 on a Thinkpad X301 for about 6
months now, with an encrypted disk that unlocks with a password at
boot time. I think that's LUKS on LVM? I didn't tinker with the
default encryption options so it's nothing too exotic: unencrypted
/boot on sda1, encrypted system/home on sda2. I've used both the
standard 3.10 kernels and 4.4 kernels from the kernel-lt package from
ELrepo with no problems so far.

When performing the update to 7.3 yesterday, the packages
kernel-lt-4.4.38-1.el7.elrepo.x86_64 and
kernel-3.10.0-514.2.2.el7.x86_64 were installed. With both of those,
my system comes to a complete, frozen halt on boot, after I've entered
my disk decryption key and before I see a login screen. The little
progress spinner freezes, and the caps lock light on my keyboard
starts blinking, which I've been told indicates a kernel panic. Any
manner of key combinations, even the "magic SysRq" combinations do
nothing to recover the system--the only way out is to cut the power. I
was able to fall back to the still-installed
4.4.36-1.el7.elrepo.x86_64 kernel with no problems. On a whim, I tried
installing the latest mainline kernel from ELrepo as well
(kernel-ml-4.9.0-1.el7.elrepo.x86_64) and encountered a similar hard
lock, minus the blinkenlight in the caps lock key.

Has anyone else had a similar issue? Is there anything in what I've
described that sounds obvious to what the solution is? It really just
seems like the problems are with kernels that have come through
following the 7.3 release. I'm still somewhat new at getting into the
inner workings of Linux, but is there a log that might shed some light
on what went wrong?

Thanks in advance,

--C

On Wed, 14 Dec 2016, Christopher St. Louis wrote:
> When performing the update to 7.3 yesterday, the packages
> kernel-lt-4.4.38-1.el7.elrepo.x86_64 and
> kernel-3.10.0-514.2.2.el7.x86_64 were installed. With both of those,
> my system comes to a complete, frozen halt on boot, after I've entered
> my disk decryption key and before I see a login screen. The little
> progress spinner freezes, and the caps lock light on my keyboard
> starts blinking, which I've been told indicates a kernel panic. Any
> manner of key combinations, even the "magic SysRq" combinations
do
> nothing to recover the system--the only way out is to cut the power. I
> was able to fall back to the still-installed
> 4.4.36-1.el7.elrepo.x86_64 kernel with no problems. On a whim, I tried
> installing the latest mainline kernel from ELrepo as well
> (kernel-ml-4.9.0-1.el7.elrepo.x86_64) and encountered a similar hard
> lock, minus the blinkenlight in the caps lock key.
>
> Has anyone else had a similar issue? Is there anything in what I've
> described that sounds obvious to what the solution is? It really just
> seems like the problems are with kernels that have come through
> following the 7.3 release. I'm still somewhat new at getting into the
> inner workings of Linux, but is there a log that might shed some light
> on what went wrong?
You need to capture the actual panic, or else it's just guessing.  Boot
without the rhgb quiet kernel args.

Also check it's not just something silly like running out os space on /boot
causing incomplete/corrupt initramfs.

jh