Segmentation fault when creating a BRIN, 10beta1

Hi,

I can reproduce a segmentation fault when creating a BRIN concurrently
with set pages_per_range and autosummarize.

# Reproduce
CREATE TABLE brin_test AS
SELECT
series AS id,
MD5(series::TEXT) AS VALUE,
'2015-10-31 13:37:00.313370+01'::TIMESTAMP + (series::TEXT || '
Minute')::INTERVAL AS TIME
FROM
GENERATE_SERIES(0,10000) AS series;

CREATE INDEX CONCURRENTLY brin_test_time_abrin_8 ON brin_test USING brin
(TIME) WITH (pages_per_range=8, autosummarize=true);

2017-05-30 16:08:59.451 CEST [20689] LOG: server process (PID 20881)
was terminated by signal 11: Segmentation fault
2017-05-30 16:08:59.451 CEST [20689] DETAIL: Failed process was
running: CREATE INDEX CONCURRENTLY brin_test_time_abrin_8 ON brin_test
USING brin (TIME) WITH (pages_per_range=8, autosummarize=true);
2017-05-30 16:08:59.451 CEST [20689] LOG: terminating any other active
server processes
2017-05-30 16:08:59.451 CEST [20806] WARNING: terminating connection
because of crash of another server process
2017-05-30 16:08:59.451 CEST [20806] DETAIL: The postmaster has
commanded this server process to roll back the current transaction and
exit, because another server process exited abnormally and possibly
corrupted shared memory.
2017-05-30 16:08:59.451 CEST [20806] HINT: In a moment you should be
able to reconnect to the database and repeat your command.
2017-05-30 16:08:59.452 CEST [21204] postgres(at)postgres FATAL: the
database system is in recovery mode

The debian packages where used, version "PostgreSQL 10beta1 on
x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18) 6.3.0 20170516,
64-bit".
I also tested the latest git commit
d5cb3bab564e0927ffac7c8729eacf181a12dd40 with the same result.
A more detailed log (debug5) can be found attached.

Kind regards,
Alexander Sosna