[Buildroot] [Bug 11001] New: loopback interface not configure properly with ifupdown-scripts + standalone ifupdown + systemd

[Buildroot] [Bug 11001] New: loopback interface not configure properly with ifupdown-scripts + standalone ifupdown + systemd

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11001

            Bug ID: 11001
           Summary: loopback interface not configure properly with
                    ifupdown-scripts + standalone ifupdown + systemd
           Product: buildroot
           Version: 2018.02
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P5
         Component: Other
          Assignee: unassigned at buildroot.uclibc.org
          Reporter: tpiepho at gmail.com
                CC: buildroot at uclibc.org
  Target Milestone: ---

If one has selected:

systemd
ifupdown-scripts
ifupdown (standalone, not work busybox)

Then the lo interface will be up, but with no address assigned.

The reason is that the systemd unit that is part of of ifupdown-scripts,
network.service, flushes the address(es) from "lo" before calling ifup -a.  It
is normal for lo to already be up, but not via ifupdown, and ifup -a will
complain  if it run in this state.  The address flush leaves "lo" in an up but
with no address state.  

In that state, busybox ifup will configure lo without complaint and give it an
address.  This is what we want.

But standalone ifup will skip the interface and not configure it.  This is not
what we want.

-- 
You are receiving this mail because:
You are on the CC list for the bug.

[Buildroot] [Bug 11001] loopback interface not configure properly with ifupdown-scripts + standalone ifupdown + systemd

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11001

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at buildroot.uclibc |yann.morin.1998 at free.fr
                   |.org                        |

-- 
You are receiving this mail because:
You are on the CC list for the bug.

[Buildroot] [Bug 11001] loopback interface not configure properly with ifupdown-scripts + standalone ifupdown + systemd

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11001

--- Comment #1 from Trent Piepho <tpiepho@gmail.com> ---
There is another issue that we discovered with the way buildroot's
network.service works with systemd.

Systemd will bring the lo interface up itself early in the boot.  Later, when
network.service runs, it will remove the address from the lo interface, as part
of the ExecStart command in network.service to do exactly that.  At this point
lo no longer has an address.  Then network.service runs ifup -a and properly
configures lo.

There a window, after the address is removed from lo and before ifup runs,
where lo is not configured correctly.  Anything that expects lo to be
configured will fail to start correctly if it happens to hit this window when
it tries to, e.g., bind a socket to an address on the lo interface.

Since the systemd init design is that lo is already up, there are services that
do this and will randomly fail.  It's not necessary to be After network.target
in order to use loopback.

-- 
You are receiving this mail because:
You are on the CC list for the bug.

[Buildroot] [Bug 11001] loopback interface not configure properly with ifupdown-scripts + standalone ifupdown + systemd

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11001

--- Comment #2 from Peter Korsgaard <jacmet@uclibc.org> ---
So what do you suggest Trent?

-- 
You are receiving this mail because:
You are on the CC list for the bug.

[Buildroot] [Bug 11001] loopback interface not configure properly with ifupdown-scripts + standalone ifupdown + systemd

[bugzilla]

https://bugs.busybox.net/show_bug.cgi?id=11001

Yann E. MORIN <yann.morin.1998@free.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |MOVED

--- Comment #3 from Yann E. MORIN <yann.morin.1998@free.fr> ---
THank you for your report.

The issue tracker for the Buildroot project has been moved to
the Gitlab.com issue tracker:
    https://gitlab.com/buildroot.org/buildroot/-/issues

We are taking this opportunity to close old issues in this old
tracker. If you believe your issue is still relevant, please
open one in the new issue tracker.

Thank you!

-- 
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot