sts-sponsors team mailing list archive

[Timo Aaltonen <tjaalton@xxxxxxxxxx>]

Hello Heitor, or anyone else affected,

Accepted dbus into xenial-proposed. The package will build now and be
available at https://launchpad.net/ubuntu/+source/dbus/1.10.6-1ubuntu3.5
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 for helping!

N.B. The updated package will be released to -updates after the bug(s)
fixed by this package have been verified and the package has been in
-proposed for a minimum of 7 days.

** Changed in: dbus (Ubuntu Xenial)
       Status: In Progress => Fix Committed

-- 
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https://bugs.launchpad.net/bugs/1846787

Title:
  systemd-logind leaves leftover sessions and scope files

Status in dbus package in Ubuntu:
  Fix Released
Status in systemd package in Ubuntu:
  Fix Released
Status in dbus source package in Xenial:
  Fix Committed
Status in systemd source package in Xenial:
  Fix Committed

Bug description:
  [Impact]
  Scope file leakage can cause SSH delays and reduce performance in systemd

  [Description]
  The current systemd-logind version present in Xenial can leave abandoned SSH
  sessions and scope files in cases where the host sees a lot of concurrent SSH
  connections. These leftover sessions can slow down systemd performance
  greatly, and can have an impact on sshd handling a great number of concurrent
  connections.

  To fix this issue, patches are needed in both dbus and systemd. These improve the
  performance of the communication between dbus and systemd, so that they can
  handle a better volume of events (e.g. SSH logins). All of those patches are
  already present from Bionic onwards, so we only need those fixes for Xenial.

  == Systemd ==
  Upstream patches:
  - core: use an AF_UNIX/SOCK_DGRAM socket for cgroup agent notification (d8fdc62037b5)

  $ git describe --contains d8fdc62037b5
  v230~71^2~2

  $ rmadison systemd
   systemd | 229-4ubuntu4     | xenial          | source, ...
   systemd | 229-4ubuntu21.21 | xenial-security | source, ...
   systemd | 229-4ubuntu21.22 | xenial-updates  | source, ... <--------
   systemd | 237-3ubuntu10    | bionic          | source, ...
   systemd | 237-3ubuntu10.29 | bionic-security | source, ...
   systemd | 237-3ubuntu10.29 | bionic-updates  | source, ...
   systemd | 237-3ubuntu10.31 | bionic-proposed | source, ...

  == DBus ==
  Upstream patches:
  - Only read one message at a time if there are fds pending (892f084eeda0)
  - bus: Fix timeout restarts  (529600397bca)
  - DBusMainLoop: ensure all required timeouts are restarted (446b0d9ac75a)

  $ git describe --contains 892f084eeda0 529600397bca 446b0d9ac75a
  dbus-1.11.10~44
  dbus-1.11.10~45
  dbus-1.11.16~2

  $ rmadison dbus
   dbus | 1.10.6-1ubuntu3    | xenial           | source, ...
   dbus | 1.10.6-1ubuntu3.4  | xenial-security  | source, ...
   dbus | 1.10.6-1ubuntu3.4  | xenial-updates   | source, ... <--------
   dbus | 1.12.2-1ubuntu1    | bionic           | source, ...
   dbus | 1.12.2-1ubuntu1.1  | bionic-security  | source, ...
   dbus | 1.12.2-1ubuntu1.1  | bionic-updates   | source, ...

  [Test Case]
  1) Simulate a lot of concurrent SSH connections with e.g. a for loop:
  multipass@xenial-logind:~$ for i in {1..1000}; do sleep 0.1; ssh localhost sleep 1 & done

  2) Check for leaked sessions in /run/systemd/system/:
  multipass@xenial-logind:~$ ls -ld /run/systemd/system/session-*.scope*
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-103.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-104.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-105.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-106.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-110.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-111.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-112.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-113.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-114.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-115.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-116.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-117.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-118.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-119.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-120.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-121.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-122.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-123.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-126.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-131.scope.d
  drwxr-xr-x 2 root root 160 Oct 4 15:34 /run/systemd/system/session-134.scope.d
  ...

  [Regression Potential]
  As the patches change the communication socket between dbus and systemd, possible regressions could cause systemd to not be notified of dbus events and vice-versa. We could see units not getting started properly, and communication between different services break down (e.g. between systemd-logind and other processes).

  In this case, the regression potential should be low as these patches
  have seen extensive testing both upstream and in more recent releases
  of Ubuntu. Nonetheless, these new packages will be rigorously tested
  through autopkgtest to avoid any possible Xenial-specific regressions.

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