Standby server crashes in master and REL9_5_STABLE branches

Hi,

Today, I found that standby server crashes with latest code of master branch and REL9_5_STABLE branch.
This happens not always but sometimes after doing pg_start_backup and pg_stop_backup for master server.

The below error messages were shown in standby server log:

FATAL:  could not access status of transaction 9009
DETAIL:  Could not read from file "pg_commit_ts/0000" at offset 90112: Success.
CONTEXT:  xlog redo Transaction/COMMIT: 2015-09-30 15:52:41.924141+09
LOG:  startup process (PID 23199) exited with exit code 1
LOG:  terminating any other active server processes

Before this FATAL, there were some INFO but annoying messages:

LOG:  file "pg_commit_ts/0000" doesn't exist, reading as zeroes
CONTEXT:  xlog redo Transaction/COMMIT: 2015-09-30 15:47:14.747566+09; inval msgs: catcache 49 catcache 49 catcache 49
catcache49
 

I cannot explain why but this crash seems to disappear if I moved HEAD to before commit
6b61955135e94b39d85571fdbb0c5a749af767f1.

Regards,

========
Takashi Ohnishi
oonishitk@nttdata.co.jp