Unknown kernel command line parameters "BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo.x86_64", will be passed to user space

[sandeepvreddy]

Hi,

On centos 7 after upgrading the kernel to version 5.18.11 I observed the below message in /var/log/messages

kernel: Kernel command line: BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo.x86_64 root=/dev/mapper/cl-root ro biosdevname=0 net.ifnames=0 crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap
Unknown kernel command line parameters "BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo.x86_64", will be passed to user space.

I couldn't get the root cause for this. Any suggestion on this.

Thanks.

 

[osprey]

For starters, you could have a look at the consistency of kernels. The one that booted is output here:

cat /proc/cmdline

The kernels on the system are usually in /boot:

ls -al /boot

The ones configured to boot are usually here:

grep linux /boot/grub/grub.cfg

If they aren't in those locations, you can seek them out in any case to check.

 

[sandeepvreddy]

For starters, you could have a look at the consistency of kernels. The one that booted is output here:

cat /proc/cmdline

The kernels on the system are usually in /boot:

ls -al /boot

The ones configured to boot are usually here:

grep linux /boot/grub/grub.cfg

If they aren't in those locations, you can seek them out in any case to check.

The files are at the expected locations. Not sure what exactly caused the above issue. Any other suggestions on this.

 

[osprey]

The kernel message "unknown kernel command line parameters" could be tested by removing one parameter at a time from your kernel line and booting to see which one, or more, the kernel is referring to by noting it's messages. Presumably, from the kernel report, one or more of those parameters is not being implemented in any case. It's a bit of "mucking around" but this approach is what comes to mind at the moment.

 

[kvdb]

I have the same issue with vanilla kernels on Debian. My guess is that distro kernels have some distro specific stuff compiled in that makes them do 'get' the kernel lines in grub. Grub uses templates for that and those are probably modified by distros as well, which might cause the issue when you boot an upstream kernel.
So - if my understanding is correct - the solution would be in modifying the grub templates. (Because this issue seems quite benign (at least in my case) I have not gotten around doing that yet.)

 

[kvdb]

Found also this: https://bugs.archlinux.org/task/72132
Seems like this is an issue between newer kernels and grub?

 

[Minx]

It is all OK.

The kernel's command-line parameters — The Linux Kernel documentation

The kernel parses parameters from the kernel command line up to "--"; if it doesn't recognize a parameter and it doesn't contain a '.', the parameter gets passed to init: parameters with '=' go into init's environment, others are passed as command line arguments to init. Everything after "--" is passed as an argument to init.

In other words:

– Kernel command line: BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo.x86_64 root=/dev/mapper/cl-root ro biosdevname=0 net.ifnames=0 crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap
– Unknown kernel command line parameters "BOOT_IMAGE=/vmlinuz-5.18.11-1.el7.elrepo.x86_64", will be passed to user space.

In essence say:

Hi there! I have parsed and handled root, ro, biosdevname, net.ifnames, crashkernel, rd.lvm.lv and rd.lvm.lv, but BOOT_IMAGE is unknown to me. I'll pass it to the environment of user space and let it utilize it as it need or want.