[Bug 1783881] Re: ltp-syscalls: msgstress03 fails because systemd limits number of processes

[Dimitri John Ledkov]

Hi,

I recommend you to change your test system.

For example, you can modify /etc/systemd/system.conf and change DefaultTasksMax there. But that is for the systemd started units...
Note that TasksMax these days can accept % values of kernel configured max tasks too, meaning i.e. one can set it to 100%..... The upstream default is 15% and we reverted that, meaning setting it to unlimited.

However something odd is going on.

I wonder if you are actually hitting UserTasksMax instead (which appears
to be under-documented).

I wonder if setting UserTasksMax=1000000 in /etc/systemd/logind.conf in
the [Login] section, restarting systemd-logind, creating a brand new
user session (logout _all_ sessions, and relogin) would actually solve
your problem?


ps. Also you can use a "drop-in" instead of modifying a config file, as all config files in systemd support .d `drop-ins` like so:

instead of modifying /etc/systemd/system.conf one can instead install
files like these:

/{lib,etc,run}/systemd/system.conf.d/bump-tasks-max.conf

with like contents of
   [Manager]
   DefaultTasksMax=1000000

Depending on whether you want it to be packaged in a package, be a
config file, or be a runtime adjustment.

** Tags added: cosmic

** No longer affects: systemd (Ubuntu Cosmic)

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https://bugs.launchpad.net/bugs/1783881

Title:
  ltp-syscalls: msgstress03 fails because systemd limits number of
  processes

Status in ubuntu-kernel-tests:
  New
Status in linux package in Ubuntu:
  Incomplete
Status in systemd package in Ubuntu:
  Incomplete
Status in linux source package in Cosmic:
  Incomplete

Bug description:
  As systemd limits the number of processes, this test will fail because
  it can't fork enough processes. That is limited to when the test is
  run after logging as user 1000, then running sudo. I guess that
  logging as root may not cause this to happen.

  # ./testcases/bin/msgstress03 
  Fork failed (may be OK if under stress)
  Fork failed (may be OK if under stress)
  msgstress03    1  TFAIL  :  msgstress03.c:157:  Fork failed (may be OK if under stress)
  #

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