Bug#961725: libopenblas-dev: On some cpus, openmp and pthread dead-lock

[Dirk Eddelbuettel]

Package: libopenblas-dev
Version: 0.3.8+ds-1
Severity: serious

This is a somewhat 'late' bug report followed several on and off discussion
threads on debian-science and/or debian-r (and started on the r-sig-debian
list from the R Project).

In short, when libopenblas-dev is installed (as e.g. from r-base-dev as a
dependency from libblas-dev, liblapack-dev) then

    libopenblas0-pthread

is installed first via our depends ranking as libopenblas-pthread-dev comes
first.

This has served us well over the years but can exhibit a bug which I for
example saw with (Ubuntun's) 0.3.8+ds-1 package. Running a simple

    example(solve)

in R hangs in an unsuspendable session (ie no Ctrl-C, kill is needed).
Simplest test is on the command-line via

    $ Rscript -e 'example(solve)'

Removing libopenbkas0-pthread and installing libopenblas-openmp-dev helps. As
does a manual reordering of the alternatives.

This bug is reproducible on my system with a i7-8700k.

The underlying issue may be Intel threading versus GNU threading which also
shows up using e.g. Intel MKL which seems happier with GNU threading.

Dirk

--
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org