Bazel build fails with "Executing genrule #six_archive//:copy_six failed" error while building syntaxnet - tensorflow

Question

I'm trying to follow the instructions at syntaxnet's github page to build syntaxnet parser models.
My system is a Debian Wheezy. Shouldn't be very different from Ubuntu 14.04 LTS or 15.05. I have compiled bazel 0.2.2 (as opposed to 0.2.2b) from source and it appears to work correctly.
Whenever I launch the bazel test syntaxnet/... util/utf8/... command, no tests are executed (all skipped) with some quite cryptic error messages. Here's an example:
root#host:~/tensorflow_syntaxnet/models/syntaxnet# ../../bazel/output/bazel test syntaxnet/... util/utf8/...
Extracting Bazel installation...
.............
INFO: Found 65 targets and 12 test targets...
ERROR: /root/.cache/bazel/_bazel_root/74c6bab7a21f28ad02405b720243d086/external/six_archive/BUILD:1:1: Executing genrule #six_archive//:copy_six failed: namespace-sandbox failed: error executing command /root/.cache/bazel/_bazel_root/74c6bab7a21f28ad02405b720243d086/syntaxnet/_bin/namespace-sandbox ... (remaining 5 argument(s) skipped).
unshare failed with EINVAL even after 101 tries, giving up.
INFO: Elapsed time: 95.469s, Critical Path: 22.46s
//syntaxnet:arc_standard_transitions_test NO STATUS
//syntaxnet:beam_reader_ops_test NO STATUS
//syntaxnet:graph_builder_test NO STATUS
//syntaxnet:lexicon_builder_test NO STATUS
//syntaxnet:parser_features_test NO STATUS
//syntaxnet:parser_trainer_test NO STATUS
//syntaxnet:reader_ops_test NO STATUS
//syntaxnet:sentence_features_test NO STATUS
//syntaxnet:shared_store_test NO STATUS
//syntaxnet:tagger_transitions_test NO STATUS
//syntaxnet:text_formats_test NO STATUS
//util/utf8:unicodetext_unittest NO STATUS
Executed 0 out of 12 tests: 12 were skipped.
I'm using Oracle Java 8 JDK as recommended, and my compiler is:
~/tensorflow_syntaxnet/models/syntaxnet# gcc --version
gcc (Debian 4.7.2-5) 4.7.2
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Tried looking into the namespace-sandbox binary that's mentioned in the error message, but before I dive deep into this, I thought I'd ask here.
~/tensorflow_syntaxnet/models/syntaxnet# ls -l /root/.cache/bazel/_bazel_root/74c6bab7a21f28ad02405b720243d086/syntaxnet/_bin/namespace-sandbox
lrwxrwxrwx 1 root root 108 May 13 14:52 /root/.cache/bazel/_bazel_root/74c6bab7a21f28ad02405b720243d086/syntaxnet/_bin/namespace-sandbox -> /root/.cache/bazel/_bazel_root/install/ca381eaad1c931167a6355cb8a2b98cf/_embedded_binaries/namespace-sandbox
~/tensorflow_syntaxnet/models/syntaxnet# readlink /root/.cache/bazel/_bazel_root/74c6bab7a21f28ad02405b720243d086/syntaxnet/_bin/namespace-sandbox
/root/.cache/bazel/_bazel_root/install/ca381eaad1c931167a6355cb8a2b98cf/_embedded_binaries/namespace-sandbox
Command seems to work fine though:
~/tensorflow_syntaxnet/models/syntaxnet# file $(readlink /root/.cache/bazel/_bazel_root/74c6bab7a21f28ad02405b720243d086/syntaxnet/_bin/namespace-sandbox)
/root/.cache/bazel/_bazel_root/install/ca381eaad1c931167a6355cb8a2b98cf/_embedded_binaries/namespace-sandbox: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.26, BuildID[md5/uuid]=0xecfd97b6a6b9a193b045be13654bd55b, not stripped
~/tensorflow_syntaxnet/models/syntaxnet# /root/.cache/bazel/_bazel_root/install/ca381eaad1c931167a6355cb8a2b98cf/_embedded_binaries/namespace-sandbox
No command specified.
Usage: /root/.cache/bazel/_bazel_root/install/ca381eaad1c931167a6355cb8a2b98cf/_embedded_binaries/namespace-sandbox [-S sandbox-root] -- command arg1
provided: /root/.cache/bazel/_bazel_root/install/ca381eaad1c931167a6355cb8a2b98cf/_embedded_binaries/namespace-sandbox
Mandatory arguments:
-S <sandbox-root> directory which will become the root of the sandbox
-- command to run inside sandbox, followed by arguments
Optional arguments:
-W <working-dir> working directory
-T <timeout> timeout after which the child process will be terminated with SIGTERM
-t <timeout> in case timeout occurs, how long to wait before killing the child with SIGKILL
-d <dir> create an empty directory in the sandbox
-M/-m <source/target> system directory to mount inside the sandbox
Multiple directories can be specified and each of them will be mounted readonly.
The -M option specifies which directory to mount, the -m option specifies where to
mount it in the sandbox.
-n if set, a new network namespace will be created
-r if set, make the uid/gid be root, otherwise use nobody
-D if set, debug info will be printed
-l <file> redirect stdout to a file
-L <file> redirect stderr to a file
#FILE read newline-separated arguments from FILE
Any idea?
UPDATE: I have done exactly the same steps on a Ubuntu 14.04 LTS (my small workstation, as opposed to the production server running Debian) and everything works well there, with all tests passing. I wonder what's the difference.

Answer 1

Apparently some permission errors happens when setting up the sandbox. A quick workaround is to deactivate the sandbox by using --genrule_strategy=standalone --spawn_strategy=standalone (note that the second one is already specified in the TensorFlow rc file).
You can set those flag in your ~/.bazelrc:
echo "build --genrule_strategy=standalone --spawn_strategy=standalone" >>~/.bazelrc