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Commit a635f431 authored by Martin Pitt's avatar Martin Pitt
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debian/README.Debian: Document how to debug boot or shutdown problems with the debug shell

Closes: #766039
parent ce68230f
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......@@ -20,3 +20,31 @@ install -d -g systemd-journal /var/log/journal
setfacl -R -nm g:adm:rx,d:g:adm:rx /var/log/journal
-- Tollef Fog Heen <tfheen@debian.org>, Wed, 12 Oct 2011 08:43:50 +0200
Debugging boot/shutdown problems
================================
The "debug-shell" service starts a root shell on VT 9 which is available very
early during boot and very late during shutdown. You can temporarily enable
this when booting the system does not get sufficiently far to get a desktop or
even the text console logins (getty), or when shutdown hangs eternally.
For boot problems the recommended way is to append "systemd.debug-shell" to the
kernel command line in the bootloader.
For shutdown problems, run "systemctl start debug-shell" as root, then shut
down.
WARNING: Please avoid "systemctl enable debug-shell" as this will start the
debug shell permanently which is a SECURITY HOLE as it allows unauthenticated
and unrestricted root access to your computer if you forget to disable it!
Please only enable it if you cannot pass "systemd.debug-shell" to the boot
loader for some reason, and then immediately run "systemctl disable debug-shell"
again.
Once the boot/shutdown problem happened, switch to VT9 (Ctrl+Alt+F9). There you
can use the usual systemctl or journalctl commands, or any other Linux shell
command to list or kill processes. For example, run "systemctl", find units
which are not in the expected state (e. g. "failed" for boot or still "active"
during shutdown), and then get more detailled information with
"systemctl status -l something.service" to get a service's status and recent
logging.
......@@ -15,6 +15,8 @@ systemd (215-6) UNRELEASED; urgency=medium
* Replace our Debian hwdb.bin location patch with what got committed
upstream. Run hwdb update with the new --usr option to keep current
behaviour.
* debian/README.Debian: Document how to debug boot or shutdown problems with
the debug shell. (Closes: #766039)
-- Martin Pitt <mpitt@debian.org> Sun, 12 Oct 2014 17:29:00 +0200
......
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