Kernel Panics


You can encounter a Kernel Panic on boot up with an ASL Kernel.

Causes for Kernel Panics

This is almost always caused by a kernel design change. For example, a module required for the system to see your disks is not being loaded in the initrd, which will cause a kernel panic.

Module names change in newer kernels, however not all distributions configure the system to use these new module names. If you experience a kernel panic your distribution is likely configured to use the older and no longer used module name(s). When the system boots it looks for these older deprecated module names and panics because it can not find them. This is a universal design condition of all Linux kernels and not specific to ASL kernels.

Diagnostics of Kernel Panics

Send the output from cat /etc/modprobe.conf and lspci to Atomicorp Support

Possible Fixes (Hardware Dependent)

Step 1: Update your modprobe.conf file by running the following command

vim /etc/modprob.conf

Step 2: Regenerate your initrd.img by running the following command

/sbin/new-kernel-pkg --package kernel --mkinitrd --depmod --install

Step 3: Set the kernel to boot into your DEFAULT OS KERNEL. NOT THE ASL KERNEL. This is defined by the “default=” value, starting at 0 for the first position. This will set the system to fail “safe” back into the working kernel, without requiring you to power cycle or otherwise cold boot the system if there is a problem.

vim /etc/grub.conf

Step 4: Set the “panic” flag on the ASL kernel line like the following

title CentOS (
  root (hd0,0)
  kernel / ro root=/dev/md0 console=tty0 console=ttyS0,57600n8 selinux=0 panic=5
  initrd /

Step 5: Set the ASL kernel to boot once, with the following grub command

[root@www2 ~]# grub

grub> savedefault --default=0 --once
grub> quit

Step 6: Reboot


If the module name is still wrong your system will boot into the default kernel you configured, which should be a non-ASL kernel that you know your distribution will boot into.