Shutdown hangs a bit in IBD

[promag]

Looks like it's related to disconnecting current nodes (?). Some logs:

2019-03-24T10:59:42Z opencon thread exit
2019-03-24T11:00:01Z dnsseed thread exit

2019-03-24T11:01:06Z net thread exit
2019-03-24T11:01:10Z opencon thread exit

[promag]

Full log with -debug:

2019-03-24T14:21:42Z Bitcoin Core version v0.18.99.0-4e748752d (release build)
2019-03-24T14:21:42Z Assuming ancestors of block 0000000000000000000f1c54590ee18d15ec70e68c8cd4cfbadb1b4f11697eee have valid signatures.
2019-03-24T14:21:42Z Setting nMinimumChainWork=0000000000000000000000000000000000000000051dc8b82f450202ecb3d471
2019-03-24T14:21:42Z Using the 'sse4(1way),sse41(4way),avx2(8way)' SHA256 implementation
2019-03-24T14:21:42Z Using RdSeed as additional entropy source
2019-03-24T14:21:42Z Using RdRand as an additional entropy source
2019-03-24T14:21:42Z Default data directory /Users/joao/Library/Application Support/Bitcoin
2019-03-24T14:21:42Z Using data directory /Users/joao/Library/Application Support/Bitcoin
2019-03-24T14:21:42Z Config file: /Users/joao/Library/Application Support/Bitcoin/bitcoin.conf (not found, skipping)
2019-03-24T14:21:42Z Using at most 125 automatic connections (4864 file descriptors available)
2019-03-24T14:21:42Z Using 16 MiB out of 32/2 requested for signature cache, able to store 524288 elements
2019-03-24T14:21:42Z Using 16 MiB out of 32/2 requested for script execution cache, able to store 524288 elements
2019-03-24T14:21:42Z Using 12 threads for script verification
2019-03-24T14:21:42Z scheduler thread start
2019-03-24T14:21:42Z Allowing HTTP connections from: 127.0.0.0/8 ::1/128
2019-03-24T14:21:42Z Binding RPC on address ::1 port 8332
2019-03-24T14:21:42Z Binding RPC on address 127.0.0.1 port 8332
2019-03-24T14:21:42Z Initialized HTTP server
2019-03-24T14:21:42Z HTTP: creating work queue of depth 16
2019-03-24T14:21:42Z Starting RPC
2019-03-24T14:21:42Z Starting HTTP RPC server
2019-03-24T14:21:42Z No rpcpassword set - using random cookie authentication.
2019-03-24T14:21:42Z Generated RPC authentication cookie /Users/joao/Library/Application Support/Bitcoin/.cookie
2019-03-24T14:21:42Z Registering HTTP handler for / (exactmatch 1)
2019-03-24T14:21:42Z Registering HTTP handler for /wallet/ (exactmatch 0)
2019-03-24T14:21:42Z Starting HTTP server
2019-03-24T14:21:42Z HTTP: starting 4 worker threads
2019-03-24T14:21:42Z Entering http event loop
2019-03-24T14:21:42Z Using wallet directory /Users/joao/Library/Application Support/Bitcoin/wallets
2019-03-24T14:21:42Z init message: Verifying wallet(s)...
2019-03-24T14:21:42Z Using BerkeleyDB version Berkeley DB 4.8.30: (April  9, 2010)
2019-03-24T14:21:42Z Using wallet /Users/joao/Library/Application Support/Bitcoin/wallets
2019-03-24T14:21:42Z BerkeleyEnvironment::Open: LogDir=/Users/joao/Library/Application Support/Bitcoin/wallets/database ErrorFile=/Users/joao/Library/Application Support/Bitcoin/wallets/db.log
2019-03-24T14:21:42Z init message: Loading banlist...
2019-03-24T14:21:42Z ERROR: DeserializeFileDB: Failed to open file /Users/joao/Library/Application Support/Bitcoin/banlist.dat
2019-03-24T14:21:42Z Invalid or missing banlist.dat; recreating
2019-03-24T14:21:42Z Flushed 0 banned node ips/subnets to banlist.dat  6ms
2019-03-24T14:21:42Z net: setting try another outbound peer=false
2019-03-24T14:21:42Z Cache configuration:
2019-03-24T14:21:42Z * Using 2.0 MiB for block index database
2019-03-24T14:21:42Z * Using 8.0 MiB for chain state database
2019-03-24T14:21:42Z * Using 440.0 MiB for in-memory UTXO set (plus up to 286.1 MiB of unused mempool space)
2019-03-24T14:21:42Z init message: Loading block index...
2019-03-24T14:21:42Z LevelDB using max_open_files=1000 (default=1000)
2019-03-24T14:21:42Z Opening LevelDB in /Users/joao/Library/Application Support/Bitcoin/blocks/index
2019-03-24T14:21:42Z leveldb: Delete type=3 #1
2019-03-24T14:21:42Z Opened LevelDB successfully
2019-03-24T14:21:42Z Using obfuscation key for /Users/joao/Library/Application Support/Bitcoin/blocks/index: 0000000000000000
2019-03-24T14:21:42Z LoadBlockIndexDB: last block file = 0
2019-03-24T14:21:42Z LoadBlockIndexDB: last block file info: CBlockFileInfo(blocks=0, size=0, heights=0...0, time=1970-01-01...1970-01-01)
2019-03-24T14:21:42Z Checking all blk files are present...
2019-03-24T14:21:42Z Initializing databases...
2019-03-24T14:21:42Z Pre-allocating up to position 0x1000000 in blk00000.dat
2019-03-24T14:21:42Z LevelDB using max_open_files=1000 (default=1000)
2019-03-24T14:21:42Z Opening LevelDB in /Users/joao/Library/Application Support/Bitcoin/chainstate
2019-03-24T14:21:42Z leveldb: Delete type=3 #1
2019-03-24T14:21:42Z Opened LevelDB successfully
2019-03-24T14:21:42Z WriteBatch memory usage: db=chainstate, before=0.0MiB, after=0.0MiB
2019-03-24T14:21:42Z Wrote new obfuscate key for /Users/joao/Library/Application Support/Bitcoin/chainstate: eab08ccd0c57ca88
2019-03-24T14:21:42Z Using obfuscation key for /Users/joao/Library/Application Support/Bitcoin/chainstate: eab08ccd0c57ca88
2019-03-24T14:21:42Z init message: Rewinding blocks...
2019-03-24T14:21:42Z  block index              55ms
2019-03-24T14:21:42Z init message: Loading wallet...
2019-03-24T14:21:42Z BerkeleyEnvironment::Open: LogDir=/Users/joao/Library/Application Support/Bitcoin/wallets/database ErrorFile=/Users/joao/Library/Application Support/Bitcoin/wallets/db.log
2019-03-24T14:21:42Z [default wallet] nFileVersion = 189900
2019-03-24T14:21:42Z [default wallet] Keys: 0 plaintext, 0 encrypted, 0 w/ metadata, 0 total. Unknown wallet records: 0
2019-03-24T14:21:42Z [default wallet] Performing wallet upgrade to 169900
2019-03-24T14:21:43Z [default wallet] keypool added 2000 keys (1000 internal), size=2000 (1000 internal)
2019-03-24T14:21:43Z [default wallet] Wallet completed loading in             989ms
2019-03-24T14:21:43Z [default wallet] setKeyPool.size() = 2000
2019-03-24T14:21:43Z [default wallet] mapWallet.size() = 0
2019-03-24T14:21:43Z [default wallet] mapAddressBook.size() = 0
2019-03-24T14:21:43Z   - Load block from disk: 0.09ms [0.00s]
2019-03-24T14:21:43Z   - Connect total: 0.07ms [0.00s (infms/blk)]
2019-03-24T14:21:43Z   - Flush: 0.03ms [0.00s (infms/blk)]
2019-03-24T14:21:43Z   - Writing chainstate: 0.02ms [0.00s (infms/blk)]
2019-03-24T14:21:43Z UpdateTip: new best=000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f height=0 version=0x00000001 log2_work=32.000022 tx=1 date='2009-01-03T18:15:05Z' progress=0.000000 cache=0.0MiB(0txo)
2019-03-24T14:21:43Z   - Connect postprocess: 0.08ms [0.00s (infms/blk)]
2019-03-24T14:21:43Z - Connect block: 0.28ms [0.00s (infms/blk)]
2019-03-24T14:21:43Z mapBlockIndex.size() = 1
2019-03-24T14:21:43Z Failed to open mempool file from disk. Continuing anyway.
2019-03-24T14:21:43Z nBestHeight = 0
2019-03-24T14:21:43Z torcontrol thread start
2019-03-24T14:21:43Z Bound to [::]:8333
2019-03-24T14:21:43Z Bound to 0.0.0.0:8333
2019-03-24T14:21:43Z init message: Loading P2P addresses...
2019-03-24T14:21:43Z ERROR: DeserializeFileDB: Failed to open file /Users/joao/Library/Application Support/Bitcoin/peers.dat
2019-03-24T14:21:43Z Invalid or missing peers.dat; recreating
2019-03-24T14:21:43Z tor: Error connecting to Tor control socket
2019-03-24T14:21:43Z tor: Not connected to Tor control port 127.0.0.1:9051, trying to reconnect
2019-03-24T14:21:43Z Flushed 0 addresses to peers.dat  6ms
2019-03-24T14:21:43Z init message: Starting network threads...
2019-03-24T14:21:43Z dnsseed thread start
2019-03-24T14:21:43Z net thread start
2019-03-24T14:21:43Z opencon thread start
2019-03-24T14:21:43Z msghand thread start
2019-03-24T14:21:43Z init message: Done loading
2019-03-24T14:21:43Z Loading addresses from DNS seeds (could take a while)
2019-03-24T14:21:43Z addcon thread start
2019-03-24T14:21:43Z Added 25 addresses from sxa35bqgjufzajdt.internal: 0 tried, 25 new
2019-03-24T14:21:43Z Added 21 addresses from 3ruqazlhqrx4izs4.internal: 0 tried, 46 new
2019-03-24T14:21:44Z trying connection 73.96.30.69:8333 lastseen=140.3hrs
^C2019-03-24T14:21:44Z Interrupting HTTP server
2019-03-24T14:21:44Z Interrupting HTTP RPC server
2019-03-24T14:21:44Z Interrupting RPC
2019-03-24T14:21:44Z tor: Thread interrupt
2019-03-24T14:21:44Z Shutdown: In progress...
2019-03-24T14:21:44Z torcontrol thread exit
2019-03-24T14:21:44Z addcon thread exit
2019-03-24T14:21:44Z Stopping HTTP RPC server
2019-03-24T14:21:44Z Unregistering HTTP handler for / (exactmatch 1)
2019-03-24T14:21:44Z Unregistering HTTP handler for /wallet/ (exactmatch 0)
2019-03-24T14:21:44Z Stopping RPC
2019-03-24T14:21:44Z RPC stopped.
2019-03-24T14:21:44Z Stopping HTTP server
2019-03-24T14:21:44Z Waiting for HTTP worker threads to exit
2019-03-24T14:21:44Z Waiting for HTTP event thread to exit
2019-03-24T14:21:44Z Exited http event loop
2019-03-24T14:21:44Z Stopped HTTP server
2019-03-24T14:21:44Z BerkeleyEnvironment::Flush: [/Users/joao/Library/Application Support/Bitcoin/wallets] Flush(false)
2019-03-24T14:21:44Z BerkeleyEnvironment::Flush: Flushing wallet.dat (refcount = 0)...
2019-03-24T14:21:44Z BerkeleyEnvironment::Flush: wallet.dat checkpoint
2019-03-24T14:21:44Z msghand thread exit
2019-03-24T14:21:44Z BerkeleyEnvironment::Flush: wallet.dat detach
2019-03-24T14:21:44Z net thread exit
2019-03-24T14:21:44Z BerkeleyEnvironment::Flush: wallet.dat closed
2019-03-24T14:21:44Z BerkeleyEnvironment::Flush: Flush(false) took              27ms
2019-03-24T14:21:44Z Added connection peer=0
2019-03-24T14:21:44Z sending version (103 bytes) peer=0
2019-03-24T14:21:44Z send version message: version 70015, blocks=0, us=[::]:0, peer=0
2019-03-24T14:21:44Z opencon thread exit

(hanged here)

2019-03-24T14:22:13Z dnsseed thread exit
2019-03-24T14:22:13Z Flushed 46 addresses to peers.dat  8ms
2019-03-24T14:22:13Z disconnecting peer=0
2019-03-24T14:22:13Z Cleared nodestate for peer=0
2019-03-24T14:22:13Z scheduler thread interrupt
2019-03-24T14:22:13Z Dumped mempool: 8e-06s to copy, 0.006101s to dump
2019-03-24T14:22:13Z Recorded 0 unconfirmed txs from mempool in 1e-06s
2019-03-24T14:22:13Z WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2019-03-24T14:22:13Z Writing final batch of 0.00 MiB
2019-03-24T14:22:13Z WriteBatch memory usage: db=chainstate, before=0.0MiB, after=0.0MiB
2019-03-24T14:22:13Z Committed 0 changed transaction outputs (out of 0) to coin database...
2019-03-24T14:22:14Z WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2019-03-24T14:22:14Z Writing final batch of 0.00 MiB
2019-03-24T14:22:14Z WriteBatch memory usage: db=chainstate, before=0.0MiB, after=0.0MiB
2019-03-24T14:22:14Z Committed 0 changed transaction outputs (out of 0) to coin database...
2019-03-24T14:22:14Z BerkeleyEnvironment::Flush: [/Users/joao/Library/Application Support/Bitcoin/wallets] Flush(true)
2019-03-24T14:22:14Z BerkeleyEnvironment::Flush: Flushing wallet.dat (refcount = 0)...
2019-03-24T14:22:14Z BerkeleyEnvironment::Flush: wallet.dat checkpoint
2019-03-24T14:22:14Z BerkeleyEnvironment::Flush: wallet.dat detach
2019-03-24T14:22:14Z BerkeleyEnvironment::Flush: wallet.dat closed
2019-03-24T14:22:14Z BerkeleyEnvironment::Flush: Flush(true) took              29ms
2019-03-24T14:22:14Z [default wallet] Releasing wallet
2019-03-24T14:22:14Z Shutdown: done

[promag]

The hanging happens in CConnman::ThreadDNSAddressSeed.