update synctrace

Makefile

@@ -61,7 +61,7 @@ ALL = $(ALL_LINUX) \
 	windows-arm64
 
 e2e:
-	$(TEST_ENV) go test -tags=e2e_testing -count=1 $(TEST_FLAGS) ./e2e
+	$(TEST_ENV) go test -tags=synctrace,e2e_testing -count=1 $(TEST_FLAGS) ./e2e
 
 e2ev: TEST_FLAGS += -v
 e2ev: e2e
@@ -215,6 +215,7 @@ ifeq ($(words $(MAKECMDGOALS)),1)
 	@$(MAKE) service ${.DEFAULT_GOAL} --no-print-directory
 endif
 
+bin-docker: BUILD_ARGS = -tags=synctrace
 bin-docker: bin build/linux-amd64/nebula build/linux-amd64/nebula-cert
 
 smoke-docker: bin-docker

config/config.go

@@ -11,12 +11,12 @@ import (
 	"sort"
 	"strconv"
 	"strings"
-	"sync"
 	"syscall"
 	"time"
 
 	"dario.cat/mergo"
 	"github.com/sirupsen/logrus"
+	"github.com/wadey/synctrace"
 	"gopkg.in/yaml.v3"
 )
 
@@ -27,13 +27,14 @@ type C struct {
 	oldSettings map[string]any
 	callbacks   []func(*C)
 	l           *logrus.Logger
-	reloadLock  sync.Mutex
+	reloadLock  synctrace.Mutex
 }
 
 func NewC(l *logrus.Logger) *C {
 	return &C{
-		Settings: make(map[string]any),
-		l:        l,
+		Settings:   make(map[string]any),
+		l:          l,
+		reloadLock: synctrace.NewMutex("config-reload"),
 	}
 }
 

connection_manager.go

@@ -5,13 +5,13 @@ import (
 	"context"
 	"encoding/binary"
 	"net/netip"
-	"sync"
 	"time"
 
 	"github.com/rcrowley/go-metrics"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/header"
+	"github.com/wadey/synctrace"
 )
 
 type trafficDecision int
@@ -28,14 +28,14 @@ const (
 
 type connectionManager struct {
 	in     map[uint32]struct{}
-	inLock *sync.RWMutex
+	inLock synctrace.RWMutex
 
 	out     map[uint32]struct{}
-	outLock *sync.RWMutex
+	outLock synctrace.RWMutex
 
 	// relayUsed holds which relay localIndexs are in use
 	relayUsed     map[uint32]struct{}
-	relayUsedLock *sync.RWMutex
+	relayUsedLock synctrace.RWMutex
 
 	hostMap                 *HostMap
 	trafficTimer            *LockingTimerWheel[uint32]
@@ -60,12 +60,12 @@ func newConnectionManager(ctx context.Context, l *logrus.Logger, intf *Interface
 	nc := &connectionManager{
 		hostMap:                 intf.hostMap,
 		in:                      make(map[uint32]struct{}),
-		inLock:                  &sync.RWMutex{},
+		inLock:                  synctrace.NewRWMutex("connection-manager-in"),
 		out:                     make(map[uint32]struct{}),
-		outLock:                 &sync.RWMutex{},
+		outLock:                 synctrace.NewRWMutex("connection-manager-out"),
 		relayUsed:               make(map[uint32]struct{}),
-		relayUsedLock:           &sync.RWMutex{},
-		trafficTimer:            NewLockingTimerWheel[uint32](time.Millisecond*500, max),
+		relayUsedLock:           synctrace.NewRWMutex("connection-manager-relay-used"),
+		trafficTimer:            NewLockingTimerWheel[uint32]("traffic-timer", time.Millisecond*500, max),
 		intf:                    intf,
 		pendingDeletion:         make(map[uint32]struct{}),
 		checkInterval:           checkInterval,

connection_state.go

@@ -4,13 +4,13 @@ import (
 	"crypto/rand"
 	"encoding/json"
 	"fmt"
-	"sync"
 	"sync/atomic"
 
 	"github.com/flynn/noise"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/noiseutil"
+	"github.com/wadey/synctrace"
 )
 
 const ReplayWindow = 1024
@@ -24,7 +24,7 @@ type ConnectionState struct {
 	initiator      bool
 	messageCounter atomic.Uint64
 	window         *Bits
-	writeLock      sync.Mutex
+	writeLock      synctrace.Mutex
 }
 
 func NewConnectionState(l *logrus.Logger, cs *CertState, crt cert.Certificate, initiator bool, pattern noise.HandshakePattern) (*ConnectionState, error) {
@@ -76,6 +76,7 @@ func NewConnectionState(l *logrus.Logger, cs *CertState, crt cert.Certificate, i
 		initiator: initiator,
 		window:    b,
 		myCert:    crt,
+		writeLock: synctrace.NewMutex("connection-state"),
 	}
 	// always start the counter from 2, as packet 1 and packet 2 are handshake packets.
 	ci.messageCounter.Add(2)

dns_server.go

@@ -6,12 +6,12 @@ import (
 	"net/netip"
 	"strconv"
 	"strings"
-	"sync"
 
 	"github.com/gaissmai/bart"
 	"github.com/miekg/dns"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/config"
+	"github.com/wadey/synctrace"
 )
 
 // This whole thing should be rewritten to use context
@@ -21,7 +21,7 @@ var dnsServer *dns.Server
 var dnsAddr string
 
 type dnsRecords struct {
-	sync.RWMutex
+	synctrace.RWMutex
 	l               *logrus.Logger
 	dnsMap4         map[string]netip.Addr
 	dnsMap6         map[string]netip.Addr
@@ -31,6 +31,7 @@ type dnsRecords struct {
 
 func newDnsRecords(l *logrus.Logger, cs *CertState, hostMap *HostMap) *dnsRecords {
 	return &dnsRecords{
+		RWMutex:         synctrace.NewRWMutex("dns-records"),
 		l:               l,
 		dnsMap4:         make(map[string]netip.Addr),
 		dnsMap6:         make(map[string]netip.Addr),

firewall.go

@@ -10,7 +10,6 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
-	"sync"
 	"time"
 
 	"github.com/gaissmai/bart"
@@ -19,6 +18,7 @@ import (
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/firewall"
+	"github.com/wadey/synctrace"
 )
 
 type FirewallInterface interface {
@@ -76,7 +76,7 @@ type firewallMetrics struct {
 }
 
 type FirewallConntrack struct {
-	sync.Mutex
+	synctrace.Mutex
 
 	Conns      map[firewall.Packet]*conn
 	TimerWheel *TimerWheel[firewall.Packet]
@@ -164,6 +164,7 @@ func NewFirewall(l *logrus.Logger, tcpTimeout, UDPTimeout, defaultTimeout time.D
 
 	return &Firewall{
 		Conntrack: &FirewallConntrack{
+			Mutex:      synctrace.NewMutex("firewall-conntrack"),
 			Conns:      make(map[firewall.Packet]*conn),
 			TimerWheel: NewTimerWheel[firewall.Packet](tmin, tmax),
 		},

go.mod

@@ -24,6 +24,7 @@ require (
 	github.com/stefanberger/go-pkcs11uri v0.0.0-20230803200340-78284954bff6
 	github.com/stretchr/testify v1.10.0
 	github.com/vishvananda/netlink v1.3.0
+	github.com/wadey/synctrace v0.0.0-20250612192159-94547ef50dfe
 	golang.org/x/crypto v0.37.0
 	golang.org/x/exp v0.0.0-20230725093048-515e97ebf090
 	golang.org/x/net v0.39.0
@@ -42,12 +43,16 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/emirpasic/gods v1.18.1 // indirect
 	github.com/google/btree v1.1.2 // indirect
+	github.com/google/uuid v1.3.0 // indirect
+	github.com/heimdalr/dag v1.4.0 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
 	github.com/prometheus/common v0.62.0 // indirect
 	github.com/prometheus/procfs v0.15.1 // indirect
+	github.com/timandy/routine v1.1.5 // indirect
 	github.com/vishvananda/netns v0.0.4 // indirect
 	golang.org/x/mod v0.23.0 // indirect
 	golang.org/x/time v0.5.0 // indirect

go.sum

@@ -22,6 +22,8 @@ github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432/go.
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/emirpasic/gods v1.18.1 h1:FXtiHYKDGKCW2KzwZKx0iC0PQmdlorYgdFG9jPXJ1Bc=
+github.com/emirpasic/gods v1.18.1/go.mod h1:8tpGGwCnJ5H4r6BWwaV6OrWmMoPhUl5jm/FMNAnJvWQ=
 github.com/flynn/noise v1.1.0 h1:KjPQoQCEFdZDiP03phOvGi11+SVVhBG2wOWAorLsstg=
 github.com/flynn/noise v1.1.0/go.mod h1:xbMo+0i6+IGbYdJhF31t2eR1BIU0CYc12+BNAKwUTag=
 github.com/gaissmai/bart v0.20.4 h1:Ik47r1fy3jRVU+1eYzKSW3ho2UgBVTVnUS8O993584U=
@@ -33,6 +35,8 @@ github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/go-test/deep v1.1.0 h1:WOcxcdHcvdgThNXjw0t76K42FXTU7HpNQWHpA2HHNlg=
+github.com/go-test/deep v1.1.0/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
@@ -58,6 +62,10 @@ github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/gopacket v1.1.19 h1:ves8RnFZPGiFnTS0uPQStjwru6uO6h+nlr9j6fL7kF8=
 github.com/google/gopacket v1.1.19/go.mod h1:iJ8V8n6KS+z2U1A8pUwu8bW5SyEMkXJB8Yo/Vo+TKTo=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/heimdalr/dag v1.4.0 h1:zG3JA4RDVLc55k3AXAgfwa+EgBNZ0TkfOO3C29Ucpmg=
+github.com/heimdalr/dag v1.4.0/go.mod h1:OCh6ghKmU0hPjtwMqWBoNxPmtRioKd1xSu7Zs4sbIqM=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@@ -145,10 +153,14 @@ github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81P
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/timandy/routine v1.1.5 h1:LSpm7Iijwb9imIPlucl4krpr2EeCeAUvifiQ9Uf5X+M=
+github.com/timandy/routine v1.1.5/go.mod h1:kXslgIosdY8LW0byTyPnenDgn4/azt2euufAq9rK51w=
 github.com/vishvananda/netlink v1.3.0 h1:X7l42GfcV4S6E4vHTsw48qbrV+9PVojNfIhZcwQdrZk=
 github.com/vishvananda/netlink v1.3.0/go.mod h1:i6NetklAujEcC6fK0JPjT8qSwWyO0HLn4UKG+hGqeJs=
 github.com/vishvananda/netns v0.0.4 h1:Oeaw1EM2JMxD51g9uhtC0D7erkIjgmj8+JZc26m1YX8=
 github.com/vishvananda/netns v0.0.4/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
+github.com/wadey/synctrace v0.0.0-20250612192159-94547ef50dfe h1:dc8Q42VsX+ABr0drJw27f3smvGfcz7eB8rJx+IkVMAo=
+github.com/wadey/synctrace v0.0.0-20250612192159-94547ef50dfe/go.mod h1:F2VCml4UxGPgAAqqm9T0ZfnVRWITrQS1EMZM+KCAm/Q=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=

handshake_ix.go

@@ -9,6 +9,7 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/header"
+	"github.com/wadey/synctrace"
 )
 
 // NOISE IX Handshakes
@@ -249,6 +250,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 		HandshakePacket:   make(map[uint8][]byte, 0),
 		lastHandshakeTime: hs.Details.Time,
 		relayState: RelayState{
+			RWMutex:        synctrace.NewRWMutex("relay-state"),
 			relays:         map[netip.Addr]struct{}{},
 			relayForByAddr: map[netip.Addr]*Relay{},
 			relayForByIdx:  map[uint32]*Relay{},

handshake_manager.go

@@ -8,7 +8,6 @@ import (
 	"errors"
 	"net/netip"
 	"slices"
-	"sync"
 	"time"
 
 	"github.com/rcrowley/go-metrics"
@@ -16,6 +15,7 @@ import (
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/udp"
+	"github.com/wadey/synctrace"
 )
 
 const (
@@ -45,7 +45,7 @@ type HandshakeConfig struct {
 
 type HandshakeManager struct {
 	// Mutex for interacting with the vpnIps and indexes maps
-	sync.RWMutex
+	synctrace.RWMutex
 
 	vpnIps  map[netip.Addr]*HandshakeHostInfo
 	indexes map[uint32]*HandshakeHostInfo
@@ -66,7 +66,7 @@ type HandshakeManager struct {
 }
 
 type HandshakeHostInfo struct {
-	sync.Mutex
+	synctrace.Mutex
 
 	startTime   time.Time        // Time that we first started trying with this handshake
 	ready       bool             // Is the handshake ready
@@ -104,6 +104,7 @@ func (hh *HandshakeHostInfo) cachePacket(l *logrus.Logger, t header.MessageType,
 
 func NewHandshakeManager(l *logrus.Logger, mainHostMap *HostMap, lightHouse *LightHouse, outside udp.Conn, config HandshakeConfig) *HandshakeManager {
 	return &HandshakeManager{
+		RWMutex:                synctrace.NewRWMutex("handshake-manager"),
 		vpnIps:                 map[netip.Addr]*HandshakeHostInfo{},
 		indexes:                map[uint32]*HandshakeHostInfo{},
 		mainHostMap:            mainHostMap,
@@ -111,7 +112,7 @@ func NewHandshakeManager(l *logrus.Logger, mainHostMap *HostMap, lightHouse *Lig
 		outside:                outside,
 		config:                 config,
 		trigger:                make(chan netip.Addr, config.triggerBuffer),
-		OutboundHandshakeTimer: NewLockingTimerWheel[netip.Addr](config.tryInterval, hsTimeout(config.retries, config.tryInterval)),
+		OutboundHandshakeTimer: NewLockingTimerWheel[netip.Addr]("outbound-handshake-timer", config.tryInterval, hsTimeout(config.retries, config.tryInterval)),
 		messageMetrics:         config.messageMetrics,
 		metricInitiated:        metrics.GetOrRegisterCounter("handshake_manager.initiated", nil),
 		metricTimedOut:         metrics.GetOrRegisterCounter("handshake_manager.timed_out", nil),
@@ -450,6 +451,7 @@ func (hm *HandshakeManager) StartHandshake(vpnAddr netip.Addr, cacheCb func(*Han
 		vpnAddrs:        []netip.Addr{vpnAddr},
 		HandshakePacket: make(map[uint8][]byte, 0),
 		relayState: RelayState{
+			RWMutex:        synctrace.NewRWMutex("relay-state"),
 			relays:         map[netip.Addr]struct{}{},
 			relayForByAddr: map[netip.Addr]*Relay{},
 			relayForByIdx:  map[uint32]*Relay{},
@@ -457,6 +459,7 @@ func (hm *HandshakeManager) StartHandshake(vpnAddr netip.Addr, cacheCb func(*Han
 	}
 
 	hh := &HandshakeHostInfo{
+		Mutex:     synctrace.NewMutex("handshake-hostinfo"),
 		hostinfo:  hostinfo,
 		startTime: time.Now(),
 	}

hostmap.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"net"
 	"net/netip"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -14,6 +13,7 @@ import (
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/header"
+	"github.com/wadey/synctrace"
 )
 
 // const ProbeLen = 100
@@ -53,20 +53,20 @@ type Relay struct {
 }
 
 type HostMap struct {
-	sync.RWMutex    //Because we concurrently read and write to our maps
-	Indexes         map[uint32]*HostInfo
-	Relays          map[uint32]*HostInfo // Maps a Relay IDX to a Relay HostInfo object
-	RemoteIndexes   map[uint32]*HostInfo
-	Hosts           map[netip.Addr]*HostInfo
-	preferredRanges atomic.Pointer[[]netip.Prefix]
-	l               *logrus.Logger
+	synctrace.RWMutex //Because we concurrently read and write to our maps
+	Indexes           map[uint32]*HostInfo
+	Relays            map[uint32]*HostInfo // Maps a Relay IDX to a Relay HostInfo object
+	RemoteIndexes     map[uint32]*HostInfo
+	Hosts             map[netip.Addr]*HostInfo
+	preferredRanges   atomic.Pointer[[]netip.Prefix]
+	l                 *logrus.Logger
 }
 
 // For synchronization, treat the pointed-to Relay struct as immutable. To edit the Relay
 // struct, make a copy of an existing value, edit the fileds in the copy, and
 // then store a pointer to the new copy in both realyForBy* maps.
 type RelayState struct {
-	sync.RWMutex
+	synctrace.RWMutex
 
 	relays map[netip.Addr]struct{} // Set of vpnAddr's of Hosts to use as relays to access this peer
 	// For data race avoidance, the contents of a *Relay are treated immutably. To update a *Relay, copy the existing data,
@@ -288,6 +288,7 @@ func NewHostMapFromConfig(l *logrus.Logger, c *config.C) *HostMap {
 
 func newHostMap(l *logrus.Logger) *HostMap {
 	return &HostMap{
+		RWMutex:       synctrace.NewRWMutex("hostmap"),
 		Indexes:       map[uint32]*HostInfo{},
 		Relays:        map[uint32]*HostInfo{},
 		RemoteIndexes: map[uint32]*HostInfo{},

lighthouse.go

@@ -9,7 +9,6 @@ import (
 	"net/netip"
 	"slices"
 	"strconv"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -21,15 +20,16 @@ import (
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/udp"
 	"github.com/slackhq/nebula/util"
+	"github.com/wadey/synctrace"
 )
 
 var ErrHostNotKnown = errors.New("host not known")
 
 type LightHouse struct {
 	//TODO: We need a timer wheel to kick out vpnAddrs that haven't reported in a long time
-	sync.RWMutex //Because we concurrently read and write to our maps
-	ctx          context.Context
-	amLighthouse bool
+	synctrace.RWMutex //Because we concurrently read and write to our maps
+	ctx               context.Context
+	amLighthouse      bool
 
 	myVpnNetworks      []netip.Prefix
 	myVpnNetworksTable *bart.Lite
@@ -96,6 +96,7 @@ func NewLightHouseFromConfig(ctx context.Context, l *logrus.Logger, c *config.C,
 	}
 
 	h := LightHouse{
+		RWMutex:            synctrace.NewRWMutex("lighthouse"),
 		ctx:                ctx,
 		amLighthouse:       amLighthouse,
 		myVpnNetworks:      cs.myVpnNetworks,
@@ -472,6 +473,7 @@ func (lh *LightHouse) QueryServer(vpnAddr netip.Addr) {
 		return
 	}
 
+	synctrace.ChanDebugSend("lighthouse-querychan")
 	lh.queryChan <- vpnAddr
 }
 
@@ -725,9 +727,11 @@ func (lh *LightHouse) startQueryWorker() {
 		nb := make([]byte, 12, 12)
 		out := make([]byte, mtu)
 
+		synctrace.ChanDebugRecvLock("lighthouse-querychan")
 		for {
 			select {
 			case <-lh.ctx.Done():
+				synctrace.ChanDebugRecvUnlock("lighthouse-querychan")
 				return
 			case addr := <-lh.queryChan:
 				lh.innerQueryServer(addr, nb, out)

outside.go

@@ -312,12 +312,11 @@ func parseV6(data []byte, incoming bool, fp *firewall.Packet) error {
 	offset := ipv6.HeaderLen // Start at the end of the ipv6 header
 	next := 0
 	for {
-		if dataLen < offset {
+		if protoAt >= dataLen {
 			break
 		}
-
 		proto := layers.IPProtocol(data[protoAt])
-		//fmt.Println(proto, protoAt)
+
 		switch proto {
 		case layers.IPProtocolICMPv6, layers.IPProtocolESP, layers.IPProtocolNoNextHeader:
 			fp.Protocol = uint8(proto)
@@ -365,7 +364,7 @@ func parseV6(data []byte, incoming bool, fp *firewall.Packet) error {
 
 		case layers.IPProtocolAH:
 			// Auth headers, used by IPSec, have a different meaning for header length
-			if dataLen < offset+1 {
+			if dataLen <= offset+1 {
 				break
 			}
 
@@ -373,7 +372,7 @@ func parseV6(data []byte, incoming bool, fp *firewall.Packet) error {
 
 		default:
 			// Normal ipv6 header length processing
-			if dataLen < offset+1 {
+			if dataLen <= offset+1 {
 				break
 			}
 

outside_test.go

@@ -117,6 +117,45 @@ func Test_newPacket_v6(t *testing.T) {
 	err = newPacket(buffer.Bytes(), true, p)
 	require.ErrorIs(t, err, ErrIPv6CouldNotFindPayload)
 
+	// A v6 packet with a hop-by-hop extension
+	// ICMPv6 Payload (Echo Request)
+	icmpLayer := layers.ICMPv6{
+		TypeCode: layers.ICMPv6TypeEchoRequest,
+	}
+	// Hop-by-Hop Extension Header
+	hopOption := layers.IPv6HopByHopOption{}
+	hopOption.OptionData = []byte{0, 0, 0, 0}
+	hopByHop := layers.IPv6HopByHop{}
+	hopByHop.Options = append(hopByHop.Options, &hopOption)
+
+	ip = layers.IPv6{
+		Version:    6,
+		HopLimit:   128,
+		NextHeader: layers.IPProtocolIPv6Destination,
+		SrcIP:      net.IPv6linklocalallrouters,
+		DstIP:      net.IPv6linklocalallnodes,
+	}
+
+	buffer.Clear()
+	err = gopacket.SerializeLayers(buffer, gopacket.SerializeOptions{
+		ComputeChecksums: false,
+		FixLengths:       true,
+	}, &ip, &hopByHop, &icmpLayer)
+	if err != nil {
+		panic(err)
+	}
+	// Ensure buffer length checks during parsing with the next 2 tests.
+
+	// A full IPv6 header and 1 byte in the first extension, but missing
+	// the length byte.
+	err = newPacket(buffer.Bytes()[:41], true, p)
+	require.ErrorIs(t, err, ErrIPv6CouldNotFindPayload)
+
+	// A full IPv6 header plus 1 full extension, but only 1 byte of the
+	// next layer, missing length byte
+	err = newPacket(buffer.Bytes()[:49], true, p)
+	require.ErrorIs(t, err, ErrIPv6CouldNotFindPayload)
+
 	// A good ICMP packet
 	ip = layers.IPv6{
 		Version:    6,
@@ -288,6 +327,10 @@ func Test_newPacket_v6(t *testing.T) {
 	assert.Equal(t, uint16(22), p.LocalPort)
 	assert.False(t, p.Fragment)
 
+	// Ensure buffer bounds checking during processing
+	err = newPacket(b[:41], true, p)
+	require.ErrorIs(t, err, ErrIPv6PacketTooShort)
+
 	// Invalid AH header
 	b = buffer.Bytes()
 	err = newPacket(b, true, p)

remote_list.go

@@ -7,11 +7,11 @@ import (
 	"slices"
 	"sort"
 	"strconv"
-	"sync"
 	"sync/atomic"
 	"time"
 
 	"github.com/sirupsen/logrus"
+	"github.com/wadey/synctrace"
 )
 
 // forEachFunc is used to benefit folks that want to do work inside the lock
@@ -185,7 +185,7 @@ func (hr *hostnamesResults) GetAddrs() []netip.AddrPort {
 // It serves as a local cache of query replies, host update notifications, and locally learned addresses
 type RemoteList struct {
 	// Every interaction with internals requires a lock!
-	sync.RWMutex
+	synctrace.RWMutex
 
 	// The full list of vpn addresses assigned to this host
 	vpnAddrs []netip.Addr
@@ -215,6 +215,7 @@ type RemoteList struct {
 // NewRemoteList creates a new empty RemoteList
 func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func(netip.Addr) bool) *RemoteList {
 	r := &RemoteList{
+		RWMutex:   synctrace.NewRWMutex("remote-list"),
 		vpnAddrs:  make([]netip.Addr, len(vpnAddrs)),
 		addrs:     make([]netip.AddrPort, 0),
 		relays:    make([]netip.Addr, 0),

sshd/server.go

@@ -5,10 +5,10 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"sync"
 
 	"github.com/armon/go-radix"
 	"github.com/sirupsen/logrus"
+	"github.com/wadey/synctrace"
 	"golang.org/x/crypto/ssh"
 )
 
@@ -28,7 +28,7 @@ type SSHServer struct {
 	listener    net.Listener
 
 	// Locks the conns/counter to avoid concurrent map access
-	connsLock sync.Mutex
+	connsLock synctrace.Mutex
 	conns     map[int]*session
 	counter   int
 }
@@ -41,6 +41,7 @@ func NewSSHServer(l *logrus.Entry) (*SSHServer, error) {
 		l:           l,
 		commands:    radix.New(),
 		conns:       make(map[int]*session),
+		connsLock:   synctrace.NewMutex("ssh-server-conns"),
 	}
 
 	cc := ssh.CertChecker{

timeout.go

@@ -1,8 +1,9 @@
 package nebula
 
 import (
-	"sync"
 	"time"
+
+	"github.com/wadey/synctrace"
 )
 
 // How many timer objects should be cached
@@ -34,7 +35,7 @@ type TimerWheel[T any] struct {
 }
 
 type LockingTimerWheel[T any] struct {
-	m sync.Mutex
+	m synctrace.Mutex
 	t *TimerWheel[T]
 }
 
@@ -81,8 +82,9 @@ func NewTimerWheel[T any](min, max time.Duration) *TimerWheel[T] {
 }
 
 // NewLockingTimerWheel is version of TimerWheel that is safe for concurrent use with a small performance penalty
-func NewLockingTimerWheel[T any](min, max time.Duration) *LockingTimerWheel[T] {
+func NewLockingTimerWheel[T any](name string, min, max time.Duration) *LockingTimerWheel[T] {
 	return &LockingTimerWheel[T]{
+		m: synctrace.NewMutex(name),
 		t: NewTimerWheel[T](min, max),
 	}
 }

udp/udp_rio_windows.go

@@ -11,13 +11,13 @@ import (
 	"io"
 	"net"
 	"net/netip"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"unsafe"
 
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/config"
+	"github.com/wadey/synctrace"
 	"golang.org/x/sys/windows"
 	"golang.zx2c4.com/wireguard/conn/winrio"
 )
@@ -46,7 +46,7 @@ type ringBuffer struct {
 	iocp       windows.Handle
 	isFull     bool
 	cq         winrio.Cq
-	mu         sync.Mutex
+	mu         synctrace.Mutex
 	overlapped windows.Overlapped
 }
 
@@ -64,7 +64,11 @@ func NewRIOListener(l *logrus.Logger, addr netip.Addr, port int) (*RIOConn, erro
 		return nil, errors.New("could not initialize winrio")
 	}
 
-	u := &RIOConn{l: l}
+	u := &RIOConn{
+		l:  l,
+		rx: ringBuffer{mu: synctrace.NewMutex("rio-rx")},
+		tx: ringBuffer{mu: synctrace.NewMutex("rio-tx")},
+	}
 
 	err := u.bind(&windows.SockaddrInet6{Addr: addr.As16(), Port: port})
 	if err != nil {