Ubuntu
systemd package

systemd should sync disks, before killing all processes on shutdown

Bug #1722481 reported by Dimitri John Ledkov on 2017-10-10

This bug affects 2 people

Affects		Status	Importance	Assigned to	Milestone
	systemd (Ubuntu)	Fix Released	Undecided	Unassigned
	Xenial	Fix Released	Undecided	Unassigned

Bug Description

[Impact]

* systemd-shutdown binary is executed to complete system shutdown. In xenial, it calls sync() after killing all processes, and not before killing them. This means that processes are racing the SIGKILL/TERM timeouts to sync all IO to disk. To mitigate this race condition, and make the shutdown process more reliable the sync() should also happen before process killing spree starts.

[Fix]
Backport upstream commit https://github.com/systemd/systemd/commit/2e79d1828a8da9b3af1b052297e3617905ec94f3

[Test Case]

* Make sure systems still shuts down, including e.g. root on raid.

[Regression Potential]

* Shutdowns may appear to be slower due to two sync() calls instead of one
* However total shutdown time should not be impacted much, as there really should not be much additional IO caused by killing all processes.

Tags:

Dimitri John Ledkov (xnox) on 2017-10-10

Changed in systemd (Ubuntu):
status:	New → Fix Released

Francis Ginther (fginther) on 2017-10-10

tags:

added: id-59dba43d6e5b35acb9bbee0b

Dimitri John Ledkov (xnox) on 2018-02-20

Changed in systemd (Ubuntu Xenial):
status:	New → In Progress

Revision history for this message

Brian Murray (brian-murray) wrote on 2018-03-08: Please test proposed package

Hello Dimitri, or anyone else affected,

Accepted systemd into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/systemd/229-4ubuntu21.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Changed in systemd (Ubuntu Xenial):
status:	In Progress → Fix Committed
tags:	added: verification-needed verification-needed-xenial

Revision history for this message

Dimitri John Ledkov (xnox) wrote on 2018-03-20:

As seen in autopkgtests, reboots are working correctly with filesystems synced to disk on shutdown, without regressions in shutdown / reboot. Thus this is sufficient to verify that the disks are still synced on shutdown.

tags:

added: verification-done verification-done-xenial
removed: verification-needed verification-needed-xenial

Revision history for this message

Launchpad Janitor (janitor) wrote on 2018-03-21:

This bug was fixed in the package systemd - 229-4ubuntu21.2

---------------
systemd (229-4ubuntu21.2) xenial; urgency=medium

  [ Dimitri John Ledkov ]
  * udev: Mark ndb devices as inactive until connected. (LP: #696435)
  * networkd: in dhcp, change UseMTU default to true, to accept DHCP provided MTU by default.
    (LP: #1717471)
  * sysctl: apply parameters in-order, instead of randomly. (LP: #1718444)
  * networkd: apply promote_secondaries, to make DHCP lease changes work.
    (LP: #1721223)
  * shutdown: sync filesystems, before going into a killing spree.
    (LP: #1722481)
  * sysctl: do not fail, when cannot apply sysctl changes due to read-only sysfs in containers.
    (LP: #1734409)
  * networkd,wait-online: add RequiredForOnline to mark mandatory/optional links for boot.
    (LP: #1737570)

[ David Glasser ]
* journald: don't reduce BurstRateLimit on low disk space (LP: #1732803)

-- Dimitri John Ledkov <email address hidden> Wed, 21 Feb 2018 13:46:37 +0000

Changed in systemd (Ubuntu Xenial):
status:	Fix Committed → Fix Released

Revision history for this message

Łukasz Zemczak (sil2100) wrote on 2018-03-21: Update Released

The verification of the Stable Release Update for systemd has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

Revision history for this message

Xeletron (xeletron) wrote on 2021-06-11:

last lines of journalctl-shutdown Edit (662 bytes, text/plain)

Is it possible this bug returned in ubuntu 21.04 - hirsute? see my systemd-shutdown in the txt file attached. ..or is a workaround possible for this?

I notice this behavior when i shutdown and reboot. the laptop needs almost no time to shutdown, and then for 20 maybe 30 seconds the plymouth screen comes back with the rotating sign, waiting to sync probably, then the screen goes black and shutdown.