一般的なトラブルシューティング

バグ報告ガイドライン

ステップバイステップデバッグガイド

デバッグ - トレースの取得

ブートデバッグ

IRC 共同デバッグ

この記事では一般的なトラブルシューティングの方法を説明しています。特定のアプリケーションの問題については、そのプログラムの wiki ページを参照してください。

注意事項

In order to resolve an issue that you are having, it is absolutely crucial to have a firm understanding of how that specific system functions. How it works, and what does it need to run without error? If you cannot comfortably answer these question then it is strongly advised that you review the Archwiki article for the function that you are having troubles with. Once you feel like you've understood the specific system, it will be easier for you to pin-point the problem.

チェックリスト

The following gives a number of questions for you whenever dealing with a malfunctioning system. Under each question there are notes explaining how you should be answering each question, followed by some light examples on how to easily gather data output and what tools can be used to review logs and the journal.

1. What is the issue(s)?

   Be as precise as possible. This will help you not get confused and/or side-tracked when looking up specific information.

2. Are there error messages? (if any)

   Copy and paste full outputs that contain error messages related to your issue into a separate file, such as $HOME/issue.log. For example, to forward the output of the following mkinitcpio command to $HOME/issue.log:

   $ mkinitcpio -p linux >> $HOME/issue.log

3. Can you reproduce the issue?

   If so, give exact step-by-step instructions/commands needed to do so.

4. When did you first encounter these issues and what was changed between then and when the system was operating without error?

   If it occurred right after an update then, list all packages that were updated. Include version numbers, also, paste the entire update from pacman.log (/var/log/pacman.log). Also take note of the statuses of any service(s) needed to support the malfunctioning application(s) using systemd's systemctl tools. For example, to forward the output of the following systemd command to $HOME/issue.log:

   $ systemctl status dhcpcd@eth0.service >> $HOME/issue.log

   ノート: Using >> will ensure any previous text in $HOME/issue.log will not be overwritten.

問題の特定

When attempting to resolve an issue, never approach it as:

Application X does not work.

Instead, look at it in its entirety:

Application X produces Y error(s) when performing Z tasks under conditions A and B.

他者のサポート

With all the information in front of you. You should have a good idea as to what is going on with the system. And you can now start working on a proper fix.

If you require any additional support, it can be found on the forums or IRC at irc.freenode.net #archlinux

セッションのパーミッション

ノート: ローカルセッションを動作させるには init システムとして systemd を使う必要があります。systemd は polkit のパーミッションや様々なデバイスの ACL を使うのに必須です (/usr/lib/udev/rules.d/70-uaccess.rules や [1] を参照)。

まず、X の中に有効なローカルセッションがあることを確認してください:

$ loginctl show-session $XDG_SESSION_ID

このコマンドの出力に Remote=no と Active=yes が含まれていなければなりません。含まれていない場合は、X がログインを行った tty と同一の tty で動作していることを確認してください。logind セッションを維持するために tty が同一である必要があります。このことはデフォルトの /etc/X11/xinit/xserverrc によって管理されています。

D-Bus セッションも X と一緒に起動する必要があります。詳しくは D-Bus#ユーザーセッションの起動 を見て下さい。

基本的な polkit のアクションはそれ以上の設定を必要としませんが、ローカルセッションだけでなく他の認証を必要とする polkit アクションも存在します。認証するには polkit 認証エージェントを実行する必要があります。詳しくは polkit#認証エージェント を見て下さい。

シングルユーザーモード

If you cannot boot due to errors caused by a daemon, display manager or Xorg, you may be able use the single user runlevel:

1. Boot to single-user mode. For GRUB 2:
   1. In the GRUB2 boot menu, select the Arch Linux entry, and press e to edit it.
   2. Find the kernel line; it will start with linux /boot/vmlinuz-linux...
   3. Appending 1 or s to this line
   4. Press F2 to start the boot process
2. Then disable the systemd service that is causing the problem.
3. Change to the multi-user mode systemd target.
4. Then try to track down the issue by running the service manually.

file: could not find any magic files!

Example: After an every-day routine update or following the installation of a package you are given the following error:

# file: could not find any magic files!

This will most likely leave your system crippled. And, any attempts made to recompile/reinstall the package(s) responsible for the breakage will fail. Also, any attempts made to try to rebuild the initramfs will result in the following:

# mkinitcpio -p linux
==> Building image from preset: 'default'
 -> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux.img
file: could not find any magic files!
==> ERROR: invalid kernel specifier: `/boot/vmlinuz-linux'
==> Building image from preset: 'fallback'
 -> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux-fallback.img -S autodetect
file: could not find any magic files!
@==> ERROR: invalid kernel specifier: `/boot/vmlinuz-linux'

解決方法

Typically a previously installed application had placed a configuration file within /etc/ld.so.conf.d/ or it had made changes to /etc/ld.so.conf which are now invalid.

1. Boot into the Arch Linux Live CD / Installation Media.
2. Mount your root (/) partition to /mnt and using arch-chroot, chroot into your system.

ノート: arch-chroot leaves mounting the /boot partition up to the user.

1. Examine /etc/ld.so.conf and remove any invalid lines found.
2. Examine the files located inside the directory /etc/ld.so.conf.d/ and remove all invalid files.
3. Rebuild the initramfs.

# mkinitcpio -p linux

1. Reboot back to your installed system.
2. Once booted, reinstall the package that was responsible for leaving your system inoperable using:

# pacman -S <package>

参照

• Fix the Most Common Problems