What is the cause for apt-get failing with returncode 137?

Question

I'm trying to build 0ad on the travis-ci service and I'm randomly experiencing failures of apt-get install (or apt-get dist-upgrade) with returncode 137 without any further information. travis-ci is based on Ubuntu 12.04. What is 137 indicating? An example output can be found at https://travis-ci.org/krichter722/0ad/jobs/92938434.

Some more system information.

$ uname -a && lsb_release -a
Linux testing-worker-linux-89e97461-1-15272-linux-4-69692739 2.6.32-042stab090.5 #1 SMP Sat Jun 21 00:15:09 MSK 2014 x86_64 x86_64 x86_64 GNU/Linux
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 12.04 LTS
Release:    12.04
Codename:    precise

Answer 1

An answer about the signal / error return status of a process... well... ok...

From the Bash man page (and generally in most shell documentation), waaay down in the section titled "Shell Grammer" and then "Simple Commands", there is an innocent statement reading thus:

The return value of a simple command is its exit status,
  or 128+n if the command is terminated by signal n.

The return value of any shell (bash, sh, dash, ksh, csh, et al) process (simple command) is an 8-bit unsigned value, with the expected range of 0-255. Typical usage customs use zero (0) as 'success', and anything else as 'error'. The shell indicates that a process was interrupted/aborted/signaled by adding 128 to the signal value and using that as the return value.

If you're old enough, you might remember getting 'Error 139' (Signal 11) aborts during a kernel compile (it USED to take all night!) if you had flaky memory or overheating issues.

Error 137 indicates the apt-get process received a signal 9 (128+9=137), and signal 9 is KILL.

If you're fuzzy on the signal names vs numbers, look at the output of the kill -l command:

$ kill -l
 1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL       5) SIGTRAP
 6) SIGABRT      7) SIGBUS       8) SIGFPE       9) SIGKILL     10) SIGUSR1
11) SIGSEGV     12) SIGUSR2     13) SIGPIPE     14) SIGALRM     15) SIGTERM
... lots more ... 64 total

Aha! Wonderful write up on Wikipedia, under Exit Status, specifically the Shell and scripts section. It explains that while a waitpid exit status of a process is an integer (int), shell processes only receive the lower 8 bits. It also talks about the '128+n' rationale. (Perhaps the wikipedia statement about ksh using '256+n' is incorrect, as the ksh man page says '128+n')

Peruse the wikipedia article, as it explains the various interpretations made by different programming languages and interfaces.

Hope this helps.

(And yes, I do read ALL the man pages, don't you?)

Addendum:

travis-ci does suggest to not use apt-get upgrade (and by extension, apt-get dist-upgrade) in the virtual machines. Install what you wish, but the VM's are generally well stocked and up-to-date.

Use of apt-get upgrade may have contributed to apt-get receiving SIGKILL. Without further information from travis-ci, we're unable to determine exactly why. But, typically... SIGKILL is used when you've done something bad, excessive resource usage, high cpu usage and the like... again, we don't know, can't tell from the logs we've seen. (As an aside, look at ulimit (in bash man page), and setrlimit/getrlimit(2) and how its various limits are handled... RLIMIT_CPU (or -t) seems appropriate here)

Answer 2

As there no error message from apt-get, I could agree with @lornix idea. But I only expect problem with available size in file-system quota or it could be the parallel download feature of apt-get. (It uses a thread for each source by default)

Here quite optimized to minimize resources (but more longer time)

uname -a && lsb_release -a && df
sudo apt-get update
sudo apt-get install python-software-properties
sudo add-apt-repository --yes ppa:wfg/0ad.dev
sudo add-apt-repository --yes ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get remove oracle-java7-installer oracle-java8-installer postgresql-9.2 postgresql-contrib-9.2 postgresql-9.2-postgis-2.1 postgresql-9.3 postgresql-contrib-9.3 postgresql-9.3-postgis-2.1 postgresql-9.4 postgresql-contrib-9.4 postgresql-9.4-postgis-2.1 postgresql-9.1 postgresql-9.1-postgis-2.1 postgresql-9.1-postgis-scripts postgresql-9.2-postgis-scripts postgresql-9.3-postgis-scripts postgresql-9.4-postgis-scripts postgresql-client postgresql-client-9.1 postgresql-client-9.2 postgresql-client-9.3 postgresql-client-9.4 postgresql-client-common postgresql-common postgresql-contrib-9.1
yes | sudo apt-get -o Acquire::Queue-mode=access -yy --yes upgrade
yes | sudo apt-get -o Acquire::Queue-mode=access -yy --yes dist-upgrade