Ubuntu Wiki

A vital part of bug triage is ensuring the required information is collected. This page should guide you as to the required information for various bug types.

General Kernel Bugs

For a general kernel bug you should ensure that the bug was filed against the linux package and contains attachments such as the dmesg file. If it does not you should request that kernel debugging information be collected and added to the bug:

• $ apport-collect -p linux <bug#>

Kernel Sound Bugs

If this is a sound related Ubuntu kernel bug, run the following to gather and attach important sound debugging information to the bug:

• $ apport-collect -p alsa-base <bug#>

Problems in capturing information

Bootloader

If the bug occurs during bootup, you can disable the splash screen in one of the following ways:

• Permanent: Edit /boot/grub/menu.lst and remove splash and quiet kernel parameters to bootloader from the entry for the buggy kernel

• Temporary: Press 'Escape' key at the 3 second pause by Grub bootloader. Then press 'e' (edit) on the buggy kernel entry, followed by 'e' again on the kernel line. Then remove the splash and quiet keywords and press 'b' to boot.

• In 10.04 and later releases, hold the right-shift key after the bios check completes to see the grub menu. Then press 'e' (edit) on the buggy kernel entry, followed by 'e' again on the kernel line. Then remove the splash and quiet keywords and press 'b' to boot.

Capturing OOPs

If the bug report involves a crash, it is hoped that a kernel backtrace (aka OOPS, kernel panic) is available. If the machine does not completely lockup from the crash, the backtrace should be available in the dmesg output. If the crash completely locks the system:

• Take a look at https://wiki.ubuntu.com/KernelTeam/CrashdumpRecipe

• If using linux-crashdump (above) is not successful try and see if any backtrace was logged to /var/log/kern.log.0. Please attach this file if anything was captured.

• If unable to log the full backtrace, supply a digital photo of the screen to capture the crash. It most important to capture the beginning of the kernel oops or panic.

• When all fails, try to see if KernelTeam/Netconsole can help out.

In X window mode

Sometimes crashes occur in X, and so terminal access is not available (to capture the kernel backtrace). When this occurs, the user should try to recreate the crash at the console (Ctrl+Alt+F1). If this is not possible, then annotate the bug as such.