segfault during consumer-rollback in failure scenario

4 node cluster_run

• load 10k items into node_1 vbucket 0
• kill node_2
• load 10k more items into node_1 vbucket 0
• kill node_1

• bring up node_2 (it will be in pending state trying to stream from node_1 which is down)
• attempt to failover node_1

• node_3 memcached crashes

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fc33ffff700 (LWP 5048)]
_GI__libc_free (mem=0xa5a5a5a5a5a5a5a5) at malloc.c:2892
2892 malloc.c: No such file or directory.

...

Thread 13 (Thread 0x7fc33ffff700 (LWP 5048)):
#0 _GI__libc_free (mem=0xa5a5a5a5a5a5a5a5) at malloc.c:2892
#1 0x00007fc34edd2456 in couchstore_close_db (db=0x7fc3300af0c0) at /home/stack/build/couchstore/src/couch_db.cc:348
#2 0x00007fc3542cda45 in CouchKVStore::closeDatabaseHandle (this=0x7fc34404e6b0, db=0x7fc3300af0c0)
at /home/stack/build/ep-engine/src/couch-kvstore/couch-kvstore.cc:2061
#3 0x00007fc3542ce686 in CouchKVStore::rollback (this=0x7fc34404e6b0, vbid=0, rollbackSeqno=10000, cb=...)
at /home/stack/build/ep-engine/src/couch-kvstore/couch-kvstore.cc:2275
#4 0x00007fc354220fbc in EventuallyPersistentStore::rollback (this=0x7fc34403ee30, vbid=0, rollbackSeqno=10000, cb=...)
at /home/stack/build/ep-engine/src/ep.cc:2916
#5 0x00007fc35429724f in UprConsumer::doRollback (this=0x7fc340000c90, st=0x7fc34403ee30, opaque=3, vbid=0, rollbackSeqno=10000)
at /home/stack/build/ep-engine/src/upr-consumer.cc:500
#6 0x00007fc354296e10 in RollbackTask::run (this=0x7fc340002080) at /home/stack/build/ep-engine/src/upr-consumer.cc:424
#7 0x00007fc35426b3d6 in ExecutorThread::run (this=0x7fc3440871b0) at /home/stack/build/ep-engine/src/executorthread.cc:94
#8 0x00007fc35426ade3 in launch_executor_thread (arg=0x7fc3440871b0) at /home/stack/build/ep-engine/src/executorthread.cc:33
#9 0x00007fc35a028933 in platform_thread_wrap (arg=0x7fc344084020) at /home/stack/build/platform/src/cb_pthreads.c:19
#10 0x00007fc358f9df6e in start_thread (arg=0x7fc33ffff700) at pthread_create.c:311
#11 0x00007fc3587ae9cd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
...

attached full gdb trace