[Ubuntu Wiki] Update of "DebuggingKernelBoot" by penalvch

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The "DebuggingKernelBoot" page has been changed by penalvch:
http://wiki.ubuntu.com/DebuggingKernelBoot?action=diff&rev1=19&rev2=20

Comment:
Due to LP#1746357 explicitly define boot looping/halt for clarity.

+ = Introduction =
+ 
  Unfortunately it is sometimes the case that your system will fail to boot due to changes within the kernel.  It is important that when submitting bug reports about these types of failures that you include the debugging information from a failed boot (not a working boot). This article will help gather this information to provide in your report.
  
- = Boot Options =
+ = Boot debugging options =
  
  When trying to capture relevant error messages that appear at boot, one may edit boot option parameters via:
  
@@ -22, +24 @@

  
  Depending on the type of error messages you encounter, there are other boot options you could try. For example, if you notice ACPI errors, try booting with the '''acpi=off''' boot option. For a full description of these options, refer to the [[https://www.kernel.org/doc/html/v4.14/admin-guide/kernel-parameters.html|kernel parameters]] document.
  
+ = Boot looping or boot halts =
+ 
+ If your boot immediately restarts, or halts, please utilize the boot debugging options and attach a video of this to your bug report.
+ 
  = Dropped into a initramfs shell =
  
  If your boot is dropped into an initramfs shell, this indicates errors in the boot sequence, for example failing to find your root partition/filesystem. You are put into the initramfs shell in an effort to allow you to recover the system. Hopefully, if you boot with the '''quiet''' and '''splash''' options removed you will notice error messages before being dropped into the shell which will help debug and direct you to a solution.
  
  If you are dropped into an initramfs shell you may want to also try booting with the '''debug''' boot option.  It should write a log to /tmp/initramfs.debug. You could also specify some arbitrary argument (for example '''debug=vc''') to have the output written to the console.
  
- Additionally, being able to extract log files from the system would be helpful. Once dropped into an initramfs shell, you can type '''httpd'''. You should then be able to point a web browser to the IP address of the system and view the contents of the /var/log folder. 
+ Additionally, being able to extract log files from the system would be helpful. Once dropped into an initramfs shell, you can type '''httpd'''. You should then be able to point a web browser to the IP address of the system and view the contents of the /var/log folder.
  
  There is another initramfs boot parameter which can purposely drop you into the initramfs shell during different stages of the initial boot sequence. The parameter is '''break=[option]''' where option can be: top, modules, premount, mount, bottom, or init. The default is premount if no options are specified. More information about the break= parameters can be found in "/usr/share/initramfs-tools/init" on your Ubuntu system.