apt segfaults when generating cache file

FWIW, you should also be able to turn off overcommitting in the kernel and/or set a ulimit -v to make things easier to reproduce.

Hello Heitor, or anyone else affected,

Accepted apt into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/apt/1.0.1ubuntu2.20 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-trusty to verification-done-trusty. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-trusty. 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.

Tested on apt-1.0.1ubuntu2.20 from trusty-proposed. Tried reproducing according to the test case from description, and verified that apt-cache does not crash:

ubuntu@apt-stress:~/stress-ng$ dpkg -l | grep apt
ii apt 1.0.1ubuntu2.20

(while having stress-ng running)
ubuntu@apt-stress:~/stress-ng$ for i in `seq 1 10000`;do apt-cache policy vsftpd;done
E: Couldn't make mmap of 30021560 bytes - MMap-mmap (12: Cannot allocate memory)
E: The package lists or status file could not be parsed or opened.

There are two armhf autopkgtest regressions for apt-1.0.1ubuntu2.20, in tests for apt [0] and autopkgtest [1]. From the autopkgtest pages we can see that these regressions were introduced long before this SRU, so it seems like a long standing issue unrelated to this patch.

[0] http://autopkgtest.ubuntu.com/packages/a/apt/trusty/armhf
[1] http://autopkgtest.ubuntu.com/packages/a/autopkgtest/trusty/armhf

This bug was fixed in the package apt - 1.0.1ubuntu2.20

---------------
apt (1.0.1ubuntu2.20) trusty; urgency=medium

  [ Julian Andres Klode ]
  * Fix crashes in apt search, cache file (LP: #1815187)
  * Clean up some build artifacts and regenerate the po files

  [ Heitor R. Alves de Siqueira ]
  * backport "do not segfault in cache generation on mmap failure"
    (Closes: 803417) (LP: #1815129)

 -- Julian Andres Klode <email address hidden> Fri, 08 Feb 2019 13:12:26 +0100

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.