unattended-upgrade might enter an infinite loop if an upgradable package is on hold

[Ludovico Cavedon]

If a package is upgradable but it is set on hold, unattende-upgrade might enter a infinite 100% CPU loop.

From the log:

2014-01-03 07:19:06,777 INFO Initial blacklisted packages: mysql-server mysql-server-5.1 mysql-server-5.5 mysql-server-core-5.1 mysql-server-core-5.5
2014-01-03 07:19:06,777 INFO Starting unattended upgrades script
2014-01-03 07:19:06,778 INFO Allowed origins are: ['o=Ubuntu,a=precise-security']
2014-01-03 07:19:09,694 INFO Initial blacklisted packages: mysql-server mysql-server-5.1 mysql-server-5.5 mysql-server-core-5.1 mysql-server-core-5.5
2014-01-03 07:19:09,694 INFO Starting unattended upgrades script
2014-01-03 07:19:09,695 INFO Allowed origins are: ['o=Ubuntu,a=precise-security']
2014-01-03 07:19:11,359 DEBUG Checking: curl (["<Origin component:'main' archive:'precise-updates' origin:'Ubuntu' label:'Ubuntu' site:'mirrors.service.softlayer.com' isTrusted:True>", "<Origin component:'main'
archive:'precise-security' origin:'Ubuntu' label:'Ubuntu' site:'mirrors.service.softlayer.com' isTrusted:True>"])
2014-01-03 07:19:11,403 DEBUG pkg 'curl' is on hold
2014-01-03 07:19:11,403 DEBUG sanity check failed
2014-01-03 07:19:12,318 DEBUG Checking: libcurl3 (["<Origin component:'main' archive:'precise-updates' origin:'Ubuntu' label:'Ubuntu' site:'mirrors.service.softlayer.com' isTrusted:True>", "<Origin component:'ma
in' archive:'precise-security' origin:'Ubuntu' label:'Ubuntu' site:'mirrors.service.softlayer.com' isTrusted:True>"])
2014-01-03 07:19:12,934 DEBUG Checking: libcurl3-gnutls (["<Origin component:'main' archive:'precise-updates' origin:'Ubuntu' label:'Ubuntu' site:'mirrors.service.softlayer.com' isTrusted:True>", "<Origin component:'main' archive:'precise-security' origin:'Ubuntu' label:'Ubuntu' site:'mirrors.service.softlayer.com' isTrusted:True>"])
2014-01-03 07:19:13,134 DEBUG pkg 'libcurl3-gnutls' is on hold
2014-01-03 07:19:13,134 DEBUG sanity check failed
2014-01-03 07:19:14,295 DEBUG pkgs that look like they should be upgraded: libcurl3
2014-01-03 07:19:14,328 DEBUG blacklist: ['mysql-server', 'mysql-server-5.1', 'mysql-server-5.5', 'mysql-server-core-5.1', 'mysql-server-core-5.5']
2014-01-03 07:19:15,102 DEBUG Checking (blacklist): libcurl3
2014-01-03 07:19:16,323 INFO Packages that are auto removed: ''
2014-01-03 07:19:16,323 DEBUG InstCount=0 DelCount=0 BrokenCout=0
2014-01-03 07:19:16,323 INFO Packages that are upgraded: libcurl3
2014-01-03 07:19:16,324 INFO Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg_2014-01-03_07:19:16.324186.log'
2014-01-03 07:19:16,350 DEBUG found partition of size 0 ([])
2014-01-03 07:19:17,118 DEBUG applying set []
2014-01-03 07:19:24,010 DEBUG left to upgrade set(['libcurl3'])
2014-01-03 07:19:24,037 DEBUG found partition of size 0 ([])
2014-01-03 07:19:24,891 DEBUG applying set []
2014-01-03 07:19:32,046 DEBUG left to upgrade set(['libcurl3'])
2014-01-03 07:19:32,080 DEBUG found partition of size 0 ([])
2014-01-03 07:19:32,939 DEBUG applying set []
2014-01-03 07:19:39,982 DEBUG left to upgrade set(['libcurl3'])
2014-01-03 07:19:40,017 DEBUG found partition of size 0 ([])
2014-01-03 07:19:40,893 DEBUG applying set []
2014-01-03 07:19:48,116 DEBUG left to upgrade set(['libcurl3'])
2014-01-03 07:19:48,149 DEBUG found partition of size 0 ([])
2014-01-03 07:19:49,002 DEBUG applying set []
2014-01-03 07:19:55,605 DEBUG left to upgrade set(['libcurl3'])
2014-01-03 07:19:55,639 DEBUG found partition of size 0 ([])

This patch seems to fix the issue:
--- /tmp/unattended-upgrade 2014-01-03 08:00:44.962143452 +0000
+++ /usr/bin/unattended-upgrade 2014-01-03 08:00:49.010144637 +0000
@@ -297,6 +297,8 @@
             else:
                 continue
             changes = [pkg.name for pkg in cache.get_changes()]
+ if not changes:
+ continue
             if len(changes) == 1:
                 logging.debug("found leaf package %s" % pkg.name)
                 smallest_partition = changes

ubuntu-bug report:
ProblemType: Bug
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Fri Jan 3 07:40:10 2014
Dependencies:
 apt 0.8.16~exp12+ll2 [origin: <myrepo>.com]
 apt-utils 0.8.16~exp12+ll2 [origin: <myrepo>.com]
 coreutils 8.13-3ubuntu3.2
 debconf 1.5.42ubuntu1
 dpkg 1.16.1.2ubuntu7.2
 gcc-4.6-base 4.6.3-1ubuntu5
 gnupg 1.4.11-3ubuntu2.5 [modified: usr/lib/gnupg/gpgkeys_curl usr/lib/gnupg/gpgkeys_hkp]
 gpgv 1.4.11-3ubuntu2.5
 libacl1 2.2.51-5ubuntu1
 libapt-inst1.4 0.8.16~exp12+ll2 [origin: <myrepo>.com]
 libapt-pkg4.12 0.8.16~exp12+ll2 [origin: <myrepo>.com]
 libattr1 1:2.4.46-5ubuntu1
 libbz2-1.0 1.0.6-1
 libc-bin 2.15-0ubuntu10.5
 libc6 2.15-0ubuntu10.5
 libdb5.1 5.1.25-11build1
 libexpat1 2.0.1-7.2ubuntu1.1
 libgcc1 1:4.6.3-1ubuntu5
 liblzma5 5.1.1alpha+20110809-3
 libncursesw5 5.9-4
 libreadline6 6.2-8
 libselinux1 2.1.0-4.1ubuntu1
 libsqlite3-0 3.7.9-2ubuntu1.1
 libssl1.0.0 1.0.1-4ubuntu5.10
 libstdc++6 4.6.3-1ubuntu5
 libtinfo5 5.9-4
 libusb-0.1-4 2:0.1.12-20
 lsb-release 4.0-0ubuntu20.3
 mime-support 3.51-1ubuntu1
 multiarch-support 2.15-0ubuntu10.5
 perl-base 5.14.2-6ubuntu2.3
 python 2.7.3-0ubuntu2.2
 python-apt 0.8.3ubuntu7.1
 python-apt-common 0.8.3ubuntu7.1
 python-minimal 2.7.3-0ubuntu2.2
 python2.7 2.7.3-0ubuntu3.4
 python2.7-minimal 2.7.3-0ubuntu3.4
 readline-common 6.2-8
 tar 1.26-4ubuntu1
 tzdata 2013g-0ubuntu0.12.04
 ubuntu-keyring 2011.11.21.1
 ucf 3.0025+nmu2ubuntu1
 xz-utils 5.1.1alpha+20110809-3
 zlib1g 1:1.2.3.4.dfsg-3ubuntu4
DistroRelease: Ubuntu 12.04
MarkForUpload: True
Package: unattended-upgrades 0.76ubuntu1 [modified: usr/bin/unattended-upgrade]
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 3.2.0-48.74-virtual 3.2.46
SourcePackage: unattended-upgrades
Tags: third-party-packages precise
Uname: Linux 3.2.0-48-virtual x86_64
UpgradeStatus: Upgraded to precise on 2013-06-28 (189 days ago)
modified.conffile..etc.apt.apt.conf.d.50unattended.upgrades:
 // Automatically upgrade packages from these (origin:archive) pairs
 Unattended-Upgrade::Allowed-Origins {
  "${distro_id}:${distro_codename}-security";
 // "${distro_id}:${distro_codename}-updates";
 // "${distro_id}:${distro_codename}-proposed";
 // "${distro_id}:${distro_codename}-backports";
 };

 // List of packages to not update
 Unattended-Upgrade::Package-Blacklist {
 // "vim";
 // "libc6";
 // "libc6-dev";
 // "libc6-i686";
         "mysql-server";
         "mysql-server-5.1";
         "mysql-server-5.5";
         "mysql-server-core-5.1";
         "mysql-server-core-5.5";
 };

 // This option allows you to control if on a unclean dpkg exit
 // unattended-upgrades will automatically run
 // dpkg --force-confold --configure -a
 // The default is true, to ensure updates keep getting installed
 Unattended-Upgrade::AutoFixInterruptedDpkg "true";

 // Split the upgrade into the smallest possible chunks so that
 // they can be interrupted with SIGUSR1. This makes the upgrade
 // a bit slower but it has the benefit that shutdown while a upgrade
 // is running is possible (with a small delay)
 Unattended-Upgrade::MinimalSteps "true";

 // Install all unattended-upgrades when the machine is shuting down
 // instead of doing it in the background while the machine is running
 // This will (obviously) make shutdown slower
 Unattended-Upgrade::InstallOnShutdown "false";

 // Send email to this address for problems or packages upgrades
 // If empty or unset then no email is sent, make sure that you
 // have a working mail setup on your system. A package that provides
 // 'mailx' must be installed.
 Unattended-Upgrade::Mail "XXXXXXX";

 // Set this value to "true" to get emails only on errors. Default
 // is to always send a mail if Unattended-Upgrade::Mail is set
 Unattended-Upgrade::MailOnlyOnError "true";

 // Do automatic removal of new unused dependencies after the upgrade
 // (equivalent to apt-get autoremove)
 Unattended-Upgrade::Remove-Unused-Dependencies "true";

 // Automatically reboot *WITHOUT CONFIRMATION* if a
 // the file /var/run/reboot-required is found after the upgrade
 Unattended-Upgrade::Automatic-Reboot "false";

 // Use apt bandwidth limit feature, this example limits the download
 // speed to 70kb/sec
 //Acquire::http::Dl-Limit "70";

mtime.conffile..etc.apt.apt.conf.d.50unattended.upgrades: 2013-06-28T01:45:43.671311

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "unattende-upgrade.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Brian Murray (brian-murray)]

Thanks for working on this and the patch. While the patch looks good I tried recreating the bug by putting an upgradeable package on hold in precise and saucy and was unable to recreate the bug. Could you provide a test case for this bug report? Thanks in advance.

[Launchpad Janitor (janitor)]

This bug was fixed in the package unattended-upgrades - 0.82.1ubuntu1

---------------
unattended-upgrades (0.82.1ubuntu1) trusty; urgency=medium

  * debian/tests/control: Add missing python-apt test dependency, so that
    tests also work with Python 2.
 -- Martin Pitt <email address hidden> Tue, 25 Feb 2014 09:45:18 +0100