cbbackupmgr does not resume once hung due to low memory

Build : 4.6.3-4047

Was running the incremental backup test with high KV ops in progress. The current step in the test was to take an incremental backup while the KV ops were ongoing. The system was low on memory at some time. cbbackupmgr got hung for almost 4-5 hrs. Then I manually released some memory by freeing up some buckets and adding some swap memory on the VM. Even after several minutes, the cbbackupmgr did not resume processing and remained stuck.

Attachment contains the output from strace, the backup dir and the backup.log