go-ethereum/p2p
zzzckck f0dc47aae3
p2p/enode: fix discovery AyncFilter deadlock on shutdown (#32572)
Description:
We found a occasionally node hang issue on BSC, I think Geth may
also have the issue, so pick the fix patch here.
The fix on BSC repo: https://github.com/bnb-chain/bsc/pull/3347

When the hang occurs, there are two routines stuck.
- routine 1: AsyncFilter(...)
On node start, it will run part of the DiscoveryV4 protocol, which could
take considerable time, here is its hang callstack:
```
goroutine 9711 [chan receive]:  // this routine was stuck on read channel: `<-f.slots`
github.com/ethereum/go-ethereum/p2p/enode.AsyncFilter.func1()
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:206 +0x125
created by github.com/ethereum/go-ethereum/p2p/enode.AsyncFilter in goroutine 1
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:192 +0x205

```

- Routine 2: Node Stop
It is the main routine to shutdown the process, but it got stuck when it
tries to shutdown the discovery components, as it tries to drain the
channel of `<-f.slots`, but the extra 1 slot will never have chance to
be resumed.
```
goroutine 11796 [chan receive]: 
github.com/ethereum/go-ethereum/p2p/enode.(*asyncFilterIter).Close.func1()
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:248 +0x5c
sync.(*Once).doSlow(0xc032a97cb8?, 0xc032a97d18?)
	sync/once.go:78 +0xab
sync.(*Once).Do(...)
	sync/once.go:69
github.com/ethereum/go-ethereum/p2p/enode.(*asyncFilterIter).Close(0xc092ff8d00?)
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:244 +0x36
github.com/ethereum/go-ethereum/p2p/enode.(*bufferIter).Close.func1()
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:299 +0x24
sync.(*Once).doSlow(0x11a175f?, 0x2bfe63e?)
	sync/once.go:78 +0xab
sync.(*Once).Do(...)
	sync/once.go:69
github.com/ethereum/go-ethereum/p2p/enode.(*bufferIter).Close(0x30?)
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:298 +0x36
github.com/ethereum/go-ethereum/p2p/enode.(*FairMix).Close(0xc0004bfea0)
	github.com/ethereum/go-ethereum/p2p/enode/iter.go:379 +0xb7
github.com/ethereum/go-ethereum/eth.(*Ethereum).Stop(0xc000997b00)
	github.com/ethereum/go-ethereum/eth/backend.go:960 +0x4a
github.com/ethereum/go-ethereum/node.(*Node).stopServices(0xc0001362a0, {0xc012e16330, 0x1, 0xc000111410?})
	github.com/ethereum/go-ethereum/node/node.go:333 +0xb3
github.com/ethereum/go-ethereum/node.(*Node).Close(0xc0001362a0)
	github.com/ethereum/go-ethereum/node/node.go:263 +0x167
created by github.com/ethereum/go-ethereum/cmd/utils.StartNode.func1.1 in goroutine 9729
	github.com/ethereum/go-ethereum/cmd/utils/cmd.go:101 +0x78
```

The rootcause of the hang is caused by the extra 1 slot, which was
designed to make sure the routines in `AsyncFilter(...)` can be
finished. This PR fixes it by making sure the extra 1 shot can always be
resumed when node shutdown.
2025-10-02 12:43:31 +02:00
..
discover p2p: using testing.B.Loop (#32664) 2025-09-19 16:38:36 -06:00
dnsdisc eth: report error from setupDiscovery at startup (#31233) 2025-02-23 17:38:32 +01:00
enode p2p/enode: fix discovery AyncFilter deadlock on shutdown (#32572) 2025-10-02 12:43:31 +02:00
enr p2p/enode: add quic ENR entry (#30283) 2024-09-13 23:47:18 +02:00
msgrate p2p: using math.MaxInt32 from go std lib (#32357) 2025-08-20 16:22:21 -06:00
nat p2p/nat: fix UPnP port reset (#31566) 2025-04-09 11:28:29 +02:00
netutil p2p: using testing.B.Loop (#32664) 2025-09-19 16:38:36 -06:00
pipes all: update license comments and AUTHORS (#31133) 2025-02-05 23:01:17 +01:00
rlpx p2p: using testing.B.Loop (#32664) 2025-09-19 16:38:36 -06:00
tracker metrics, cmd/geth: change init-process of metrics (#30814) 2024-12-10 13:27:29 +01:00
config.go p2p: update MaxPeers comment (#32414) 2025-08-19 20:14:11 +08:00
config_toml.go p2p: support configuring NAT in TOML file (#31041) 2025-01-22 09:29:34 +01:00
dial.go p2p: DNS resolution for static nodes (#30822) 2024-12-13 12:46:12 +01:00
dial_test.go p2p: DNS resolution for static nodes (#30822) 2024-12-13 12:46:12 +01:00
message.go p2p: use atomic types (#27764) 2023-08-01 23:20:52 +02:00
message_test.go p2p: move rlpx into separate package (#21464) 2020-09-22 10:17:39 +02:00
metrics.go p2p: add metrics for inbound connection errors (#31652) 2025-05-07 15:34:52 +02:00
peer.go p2p: remove todo comment, as it's unnecessary (#32397) 2025-08-21 15:48:46 -06:00
peer_error.go p2p: fix DiscReason encoding/decoding (#30855) 2024-12-12 12:33:42 +01:00
peer_test.go p2p: DNS resolution for static nodes (#30822) 2024-12-13 12:46:12 +01:00
protocol.go all: use cmp.Compare (#30958) 2025-01-02 14:06:47 +01:00
server.go eth, p2p: improve dial speed by pre-fetching dial candidates (#31944) 2025-06-05 12:14:35 +02:00
server_nat.go p2p/nat: fix UPnP port reset (#31566) 2025-04-09 11:28:29 +02:00
server_nat_test.go p2p: fix flaky test TestServerPortMapping (#30241) 2024-07-30 07:31:27 -06:00
server_test.go p2p: fix dial metrics not picking up the right error (#31621) 2025-04-15 20:40:30 +02:00
transport.go p2p: fix DiscReason encoding/decoding (#30855) 2024-12-12 12:33:42 +01:00
transport_test.go p2p: fix DiscReason encoding/decoding (#30855) 2024-12-12 12:33:42 +01:00
util.go all: assign zero after resize in implementations of heap.Interface (#26296) 2022-12-05 13:49:54 +01:00
util_test.go p2p: new dial scheduler (#20592) 2020-02-13 11:10:03 +01:00