Package 'unbound' was added to gnu/packages/dns.scm with version 1.6.3
in commit

ed690bc9116db3ff269353ea0b16cbca54b045cf

Since then it is failing in Hydra for x86_64 and i686:

https://hydra.gnu.org/job/gnu/master/unbound-1.6.3.x86_64-linux/all
https://hydra.gnu.org/job/gnu/master/unbound-1.6.8.x86_64-linux/all

https://hydra.gnu.org/job/gnu/master/unbound-1.6.3.i686-linux/all
https://hydra.gnu.org/job/gnu/master/unbound-1.6.8.i686-linux/all

Tail of log of https://hydra.gnu.org/build/2521795#tabs-summary

libtool: link: gcc -I. -I/gnu/store/3lkypf5wnsnvkaidhw0pv7k3yjfh1r9g-python-3.6.3/include/python3.6m -I/gnu/store/9fgzlp4n9419f0q7gw5vz1ss0gw0jmxp-openssl-1.0.2n/include -I/gnu/store/vkc9mp2k7kx3vbba0nqdbvx4j418851w-libevent-2.1.8/include -I/gnu/store/lqsnx83pynnyx0fihadz79xy1smlpvmp-expat-2.2.5/include -g -O2 -flto -pthread -o testbound .libs/testbound.o .libs/replay.o .libs/fake_event.o .libs/testpkts.o .libs/worker.o .libs/acl_list.o .libs/daemon.o .libs/stats.o .libs/shm_main.o .libs/dns.o .libs/infra.o .libs/rrset.o .libs/dname.o .libs/msgencode.o .libs/as112.o .libs/msgparse.o .libs/msgreply.o .libs/packed_rrset.o .libs/iterator.o .libs/iter_delegpt.o .libs/iter_donotq.o .libs/iter_fwd.o .libs/iter_hints.o .libs/iter_priv.o .libs/iter_resptype.o .libs/iter_scrub.o .libs/iter_utils.o .libs/localzone.o .libs/mesh.o .libs/modstack.o .libs/view.o .libs/outbound_list.o .libs/alloc.o .libs/config_file.o .libs/configlexer.o .libs/configparser.o .libs/fptr_wlist.o .libs/locks.o .libs/log.o .libs/mini_event.o .libs/module.o .libs/net_help.o .libs/random.o .libs/rbtree.o .libs/regional.o .libs/rtt.o .libs/dnstree.o .libs/lookup3.o .libs/lruhash.o .libs/slabhash.o .libs/timehist.o .libs/tube.o .libs/winsock_event.o .libs/autotrust.o .libs/val_anchor.o .libs/validator.o .libs/val_kcache.o .libs/val_kentry.o .libs/val_neg.o .libs/val_nsec3.o .libs/val_nsec.o .libs/val_secalgo.o .libs/val_sigcrypt.o .libs/val_utils.o .libs/dns64.o .libs/cachedb.o .libs/authzone.o .libs/pythonmod.o .libs/pythonmod_utils.o .libs/respip.o .libs/ub_event.o .libs/keyraw.o .libs/sbuffer.o .libs/wire2str.o .libs/parse.o .libs/parseutil.o .libs/rrdef.o .libs/str2wire.o .libs/strlcat.o .libs/strlcpy.o .libs/arc4random.o .libs/arc4random_uniform.o .libs/explicit_bzero.o .libs/arc4_lock.o  -L/gnu/store/9fgzlp4n9419f0q7gw5vz1ss0gw0jmxp-openssl-1.0.2n/lib -L/gnu/store/vkc9mp2k7kx3vbba0nqdbvx4j418851w-libevent-2.1.8/lib -L/gnu/store/lqsnx83pynnyx0fihadz79xy1smlpvmp-expat-2.2.5/lib -lssl /gnu/store/vkc9mp2k7kx3vbba0nqdbvx4j418851w-libevent-2.1.8/lib/libevent.so -L/gnu/store/3lkypf5wnsnvkaidhw0pv7k3yjfh1r9g-python-3.6.3/lib -L/gnu/store/3lkypf5wnsnvkaidhw0pv7k3yjfh1r9g-python-3.6.3/lib/python3.6 -L. -lpython3.6m -lcrypto -pthread -Wl,-rpath -Wl,/gnu/store/vkc9mp2k7kx3vbba0nqdbvx4j418851w-libevent-2.1.8/lib -Wl,-rpath -Wl,/gnu/store/vkc9mp2k7kx3vbba0nqdbvx4j418851w-libevent-2.1.8/lib -Wl,-rpath -Wl,/gnu/store/9fgzlp4n9419f0q7gw5vz1ss0gw0jmxp-openssl-1.0.2n/lib
LD_PRELOAD=/tmp/nss_preload.so ./unittest
make: *** [Makefile:308: test] Killed
phase `check' failed after 22.8 seconds
builder for `/gnu/store/9nb5pq1k0ckjxa5gd91m8nmfcr7hx95b-unbound-1.6.8.drv' failed with exit code 1
@ build-failed /gnu/store/9nb5pq1k0ckjxa5gd91m8nmfcr7hx95b-unbound-1.6.8.drv - 1 builder for `/gnu/store/9nb5pq1k0ckjxa5gd91m8nmfcr7hx95b-unbound-1.6.8.drv' failed with exit code 1

I locally checked out commit 629daea9818fc585afce557645958b33774f2729
and cannot reproduce this problem.

Also, https://berlin.guixsd.org has it as a substitute (on x86_64 at least).

On armhf, 2 out of 5 builds were successfull:

https://hydra.gnu.org/job/gnu/master/unbound-1.6.3.armhf-linux/all
https://hydra.gnu.org/job/gnu/master/unbound-1.6.8.armhf-linux/all

At least this one failed with the same error message:

https://hydra.gnu.org/build/2452561/log/raw

Is this a problem of the environment/machine? Out of Memory?

I built it locally 20 times without problems or any memory-peaks.

Björn