Indexer exited fatal error: unexpected signal in fdb_get_kv

system testing with 4.5.0-1958
8 node cluster, 4 buckets with primary indexes.

Querying index started to fail due to index crash and attempts to restart index cause subsequent failures. (attached indexer log)

fatal error: unexpected signal during runtime execution
[signal 0xb code=0x1 addr=0x2 pc=0x7f0bb2817dca]

runtime stack:
runtime.throw(0x11e9420, 0x2a)
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.6/go/src/runtime/panic.go:530 +0x90 fp=0x7f0baf78f670 sp=0x7f0baf78f658
runtime.sigpanic()
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.6/go/src/runtime/sigpanic_unix.go:12 +0x5a fp=0x7f0baf78f6c0 sp=0x7f0baf78f670

goroutine 350 [syscall, locked to thread]:
runtime.cgocall(0xc69ec8, 0xc824d77988, 0xc800000000)
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.6/go/src/runtime/cgocall.go:123 +0x11b fp=0xc824d77938 sp=0xc824d77908
github.com/couchbase/indexing/secondary/fdb._Cfunc_fdb_get_kv(0x7f0bac4194c0, 0xc823abf4e0, 0x11, 0xc88ff6c838, 0xc88ff84ae8, 0xc800000000)
??:0 +0x41 fp=0xc824d77988 sp=0xc824d77938
github.com/couchbase/indexing/secondary/fdb.(*KVStore).GetKV(0xc824b2d170, 0xc823abf4e0, 0x11, 0x11, 0x0, 0x0, 0x0, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/indexing/secondary/fdb/kv.go:36 +0x2e9 fp=0xc824d77a58 sp=0xc824d77988
github.com/couchbase/indexing/secondary/indexer.(*fdbSlice).getBackIndexEntry(0xc82012d680, 0xc823abf4e0, 0x11, 0x11, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/forestdb_slice_writer.go:788 +0x115 fp=0xc824d77b20 sp=0xc824d77a58
github.com/couchbase/indexing/secondary/indexer.(*fdbSlice).deleteSecIndex(0xc82012d680, 0xc823abf4e0, 0x11, 0x11, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/forestdb_slice_writer.go:665 +0x99 fp=0xc824d77d00 sp=0xc824d77b20
github.com/couchbase/indexing/secondary/indexer.(*fdbSlice).delete(0xc82012d680, 0xc823abf4e0, 0x11, 0x11, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/forestdb_slice_writer.go:618 +0xa9 fp=0xc824d77d40 sp=0xc824d77d00
github.com/couchbase/indexing/secondary/indexer.(*fdbSlice).handleCommandsWorker(0xc82012d680, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/forestdb_slice_writer.go:321 +0x314 fp=0xc824d77f90 sp=0xc824d77d40
runtime.goexit()
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.6/go/src/runtime/asm_amd64.s:1998 +0x1 fp=0xc824d77f98 sp=0xc824d77f90
created by github.com/couchbase/indexing/secondary/indexer.NewForestDBSlice
/home/couchbase/jenkins/