[Pkg-utopia-maintainers] Bug#842606: ostree pull or pull-local intermittently does not terminate (e.g. FTBFS with exit status 124)

[Simon McVittie]

Source: ostree
Version: 2016.12-1
Severity: important

"ostree pull" and related commands sometimes lock up (deadlock?) and do
not terminate. This can sometimes also be seen in Flatpak, which uses
ostree behind the scenes.

When tests are run at build-time, we use timeout(1) to kill each test
after 30 minutes. This lockup manifests as exit status 124, for example
in these build logs:

https://buildd.debian.org/status/fetch.php?pkg=ostree&arch=amd64&ver=2016.12-1&stamp=1477511802
https://buildd.debian.org/status/fetch.php?pkg=ostree&arch=powerpcspe&ver=2016.12-1&stamp=1477523854

My speculation is that this might be another manifestation of the same
non-thread-safe communication (between the main thread and a libsoup
worker thread perhaps?) that is causing segfaults in "ostree pull"
(also visible in that amd64 log); but I have no evidence for this.

Unhelpfully, I cannot reproduce either the deadlocks or the segfaults
on-demand. If anyone can reproduce them reliably, backtraces and
debugging would be very useful.

ci.debian.net also appears to see timeouts in the tests reliably,
but I don't know how to retrieve useful debug information from there.

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental-debug'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.7.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

-- no debconf information