pkgCacheFile unlocks in destructor even if it did not acquire lock
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
| apt (Ubuntu) |
High
|
Julian Andres Klode | ||
| Trusty |
High
|
Unassigned | ||
| Xenial |
High
|
Unassigned | ||
| Bionic |
High
|
Unassigned | ||
| Cosmic |
High
|
Julian Andres Klode |
Bug Description
[Impact]
Closing a cache file unlocks the system (loses the lock). This randomly breaks ubuntu-make, for example.
[Test case]
The following Python code fails, but should succeed, as it locks first, opens a cache and closes it, and then unlocks.
import apt_pkg, os, gc
apt_pkg.init()
apt_pkg.
os.system("ls -l /proc/%d/fd" % os.getpid())
apt_pkg.Cache()
gc.collect()
os.system("ls -l /proc/%d/fd" % os.getpid())
apt_pkg.
[Regression potential]
This fixes a regression introduced in 2001 by
commit b2e465d6d32d2dc
Author: Arch Librarian <email address hidden>
Date: Mon Sep 20 16:56:32 2004 +0000
Join with aliencode
Author: jgg
Date: 2001-02-20 07:03:16 GMT
Join with aliencode
The fix is to only UnLock from the cache file if the cache file locked before. It's unclear how far code relies on that regression. That said, any potential regression should be easily noticable, as it would be a case of not unlocking where we were unlocking before.
Changed in apt (Ubuntu): | |
importance: | Undecided → High |
status: | New → In Progress |
assignee: | nobody → Julian Andres Klode (juliank) |
Changed in apt (Ubuntu Bionic): | |
importance: | Undecided → High |
Changed in apt (Ubuntu Xenial): | |
importance: | Undecided → High |
Changed in apt (Ubuntu Trusty): | |
importance: | Undecided → High |
status: | New → Triaged |
Changed in apt (Ubuntu Xenial): | |
status: | New → Triaged |
Changed in apt (Ubuntu Bionic): | |
status: | New → Triaged |
Changed in apt (Ubuntu Cosmic): | |
status: | In Progress → Fix Committed |
Launchpad Janitor (janitor) wrote : | #1 |
Changed in apt (Ubuntu Cosmic): | |
status: | Fix Committed → Fix Released |
Hello Julian, or anyone else affected,
Accepted apt into bionic-proposed. The package will build now and be available at https:/
Please help us by testing this new package. See https:/
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-
Further information regarding the verification process can be found at https:/
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 apt (Ubuntu Bionic): | |
status: | Triaged → Fix Committed |
tags: | added: verification-needed verification-needed-bionic |
Łukasz Zemczak (sil2100) wrote : | #3 |
Hello Julian, or anyone else affected,
Accepted apt into xenial-proposed. The package will build now and be available at https:/
Please help us by testing this new package. See https:/
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-
Further information regarding the verification process can be found at https:/
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 apt (Ubuntu Xenial): | |
status: | Triaged → Fix Committed |
tags: | added: verification-needed-xenial |
Brian Murray (brian-murray) wrote : | #4 |
Hello Julian, or anyone else affected,
Accepted apt into xenial-proposed. The package will build now and be available at https:/
Please help us by testing this new package. See https:/
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-
Further information regarding the verification process can be found at https:/
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.
Brian Murray (brian-murray) wrote : | #5 |
Hello Julian, or anyone else affected,
Accepted apt into bionic-proposed. The package will build now and be available at https:/
Please help us by testing this new package. See https:/
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-
Further information regarding the verification process can be found at https:/
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.
Julian Andres Klode (juliank) wrote : | #6 |
bionic (1.6.3ubuntu0.1 -> 1.6.6):
root@dashing-
total 0
[...]
lrwx------ 1 root root 64 Oct 18 12:07 3 -> /var/lib/dpkg/lock
l-wx------ 1 root root 64 Oct 18 12:07 6 -> 'pipe:[27578280]'
Reading package lists... Done
Building dependency tree
Reading state information... Done
total 0
[...]
l-wx------ 1 root root 64 Oct 18 12:07 6 -> 'pipe:[27578280]'
Traceback (most recent call last):
File "a.py", line 13, in <module>
apt_
apt_pkg.Error: E:Not locked
[...]
=> We can see that the cache was already unlocked when it should not have been
root@dashing-
[...]
Unpacking libapt-pkg5.0:amd64 (1.6.6) over (1.6.3ubuntu0.1) ...
[...]
root@dashing-
total 0
[...]
lrwx------ 1 root root 64 Oct 18 12:08 3 -> /var/lib/
lrwx------ 1 root root 64 Oct 18 12:08 4 -> /var/lib/dpkg/lock
l-wx------ 1 root root 64 Oct 18 12:08 6 -> 'pipe:[27578280]'
Reading package lists... Done
Building dependency tree
Reading state information... Done
total 0
[...]
lrwx------ 1 root root 64 Oct 18 12:08 3 -> /var/lib/
lrwx------ 1 root root 64 Oct 18 12:08 4 -> /var/lib/dpkg/lock
l-wx------ 1 root root 64 Oct 18 12:08 6 -> 'pipe:[27578280]'
root@dashing-
=> script worked fine, we see that the lock is still open in the second ls, and there are no error messages
tags: |
added: verification-done-bionic removed: verification-needed-bionic |
Julian Andres Klode (juliank) wrote : | #7 |
xenial
======
With 1.2.27
-----------
root@glowing-
total 0
[...]
lrwx------ 1 root root 64 Oct 18 12:15 3 -> /var/lib/dpkg/lock
l-wx------ 1 root root 64 Oct 18 12:15 6 -> pipe:[27632799]
Reading package lists... Done
Building dependency tree
Reading state information... Done
total 0
[...]
l-wx------ 1 root root 64 Oct 18 12:15 6 -> pipe:[27632799]
Traceback (most recent call last):
File "a.py", line 13, in <module>
apt_
SystemError: E:Not locked
=> broken as expected
With 1.2.29
-----------
root@glowing-
total 0
[...]
lrwx------ 1 root root 64 Oct 18 12:17 3 -> /var/lib/
lrwx------ 1 root root 64 Oct 18 12:17 4 -> /var/lib/dpkg/lock
l-wx------ 1 root root 64 Oct 18 12:17 6 -> pipe:[27632799]
Reading package lists... Done
Building dependency tree
Reading state information... Done
total 0
[...]
lrwx------ 1 root root 64 Oct 18 12:17 3 -> /var/lib/
lrwx------ 1 root root 64 Oct 18 12:17 4 -> /var/lib/dpkg/lock
l-wx------ 1 root root 64 Oct 18 12:17 6 -> pipe:[27632799]
root@glowing-
=> lock is still held at second ls, and releasing it worked fine.
tags: |
added: verification-done verification-done-xenial removed: verification-needed verification-needed-xenial |
Launchpad Janitor (janitor) wrote : | #8 |
This bug was fixed in the package apt - 1.6.6
---------------
apt (1.6.6) bionic; urgency=medium
* Set DPKG_FRONTEND_
Some post-invoke scripts install packages, which fails because
the environment variable is not set. This sets the variable for
all three kinds of scripts {pre,post-}invoke and pre-install-pkgs,
but we will only allow post-invoke at a later time.
(LP: #1796808)
apt (1.6.5) bionic; urgency=medium
[ David Kalnischkies ]
* Support records larger than 32kb in 'apt show' (Closes: #905527)
(LP: #1787120)
[ Julian Andres Klode ]
* Add support for dpkg frontend lock (Closes: #869546) (LP: #1781169)
* Set DPKG_FRONTEND_
* http: Stop pipeline after close only if it was not filled before
(LP: #1794957)
* pkgCacheFile: Only unlock in destructor if locked before (LP: #1794053)
* Update libapt-pkg5.0 symbols for frontend locking
-- Julian Andres Klode <email address hidden> Tue, 09 Oct 2018 12:16:51 +0200
Changed in apt (Ubuntu Bionic): | |
status: | Fix Committed → Fix Released |
The verification of the Stable Release Update for apt 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.
Launchpad Janitor (janitor) wrote : | #10 |
This bug was fixed in the package apt - 1.2.29
---------------
apt (1.2.29) xenial; urgency=medium
* Set DPKG_FRONTEND_
Some post-invoke scripts install packages, which fails because
the environment variable is not set. This sets the variable for
all three kinds of scripts {pre,post-}invoke and pre-install-pkgs,
but we will only allow post-invoke at a later time.
(LP: #1796808)
apt (1.2.28) xenial; urgency=medium
[ Julian Andres Klode ]
* apt.conf.
* Add support for dpkg frontend lock (Closes: #869546) (LP: #1781169)
* Set DPKG_FRONTEND_
* http: Stop pipeline after close only if it was not filled before
(LP: #1794957)
* pkgCacheFile: Only unlock in destructor if locked before (LP: #1794053)
* Update libapt-pkg5.0 symbols for frontend locking
[ David Kalnischkies ]
* Support records larger than 32kb in 'apt show' (Closes: #905527)
(LP: #1787120)
-- Julian Andres Klode <email address hidden> Tue, 09 Oct 2018 12:35:03 +0200
Changed in apt (Ubuntu Xenial): | |
status: | Fix Committed → Fix Released |
This bug was fixed in the package apt - 1.7.0~rc2ubuntu1
---------------
apt (1.7.0~rc2ubuntu1) cosmic; urgency=medium
* Fix calculation of elapsed usec in downloads
* pkgCacheFile: Only unlock in destructor if locked before (LP: #1794053)
-- Julian Andres Klode <email address hidden> Mon, 24 Sep 2018 12:18:26 +0200