From 1abc68ccf42794756a61e7c2e850051e79b5a1e0 Mon Sep 17 00:00:00 2001
From: Kristoffer Dalby <kradalby@kradalby.no>
Date: Thu, 5 Aug 2021 22:14:37 +0100
Subject: [PATCH] Removes locks causing deadlock
This commit removes most of the locks in the PollingMap handler as there
was combinations that caused deadlocks. Instead of doing a plain map and
doing the locking ourselves, we use sync.Map which handles it for us.
---
api.go | 14 ++++----------
app.go | 3 +--
namespaces.go | 6 ++----
routes.go | 4 ++--
4 files changed, 9 insertions(+), 18 deletions(-)
diff --git a/api.go b/api.go
index 9fd8c7bf..8589d07c 100644
--- a/api.go
+++ b/api.go
@@ -299,9 +299,7 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
Str("id", c.Param("id")).
Str("machine", m.Name).
Msg("Locking poll mutex")
- h.pollMu.Lock()
- h.clientsPolling[m.ID] = update
- h.pollMu.Unlock()
+ h.clientsPolling.Store(m.ID, update)
log.Trace().
Str("handler", "PollNetMap").
Str("id", c.Param("id")).
@@ -373,9 +371,8 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
Str("machine", m.Name).
Msg("Notifying peers")
peers, _ := h.getPeers(m)
- h.pollMu.Lock()
for _, p := range *peers {
- pUp, ok := h.clientsPolling[uint64(p.ID)]
+ pUp, ok := h.clientsPolling.Load(uint64(p.ID))
if ok {
log.Info().
Str("handler", "PollNetMap").
@@ -383,7 +380,7 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
Str("peer", m.Name).
Str("address", p.Addresses[0].String()).
Msgf("Notifying peer %s (%s)", p.Name, p.Addresses[0])
- pUp <- []byte{}
+ pUp.(chan []byte) <- []byte{}
} else {
log.Info().
Str("handler", "PollNetMap").
@@ -392,7 +389,6 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
Msgf("Peer %s does not appear to be polling", p.Name)
}
}
- h.pollMu.Unlock()
go h.keepAlive(cancelKeepAlive, pollData, mKey, req, m)
@@ -448,11 +444,9 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
now := time.Now().UTC()
m.LastSeen = &now
h.db.Save(&m)
- h.pollMu.Lock()
cancelKeepAlive <- []byte{}
- delete(h.clientsPolling, m.ID)
+ h.clientsPolling.Delete(m.ID)
close(update)
- h.pollMu.Unlock()
return false
}
diff --git a/app.go b/app.go
index 45df01c0..668e23b9 100644
--- a/app.go
+++ b/app.go
@@ -59,7 +59,7 @@ type Headscale struct {
aclRules *[]tailcfg.FilterRule
pollMu sync.Mutex
- clientsPolling map[uint64]chan []byte // this is by all means a hackity hack
+ clientsPolling sync.Map
}
// NewHeadscale returns the Headscale app
@@ -99,7 +99,6 @@ func NewHeadscale(cfg Config) (*Headscale, error) {
return nil, err
}
- h.clientsPolling = make(map[uint64]chan []byte)
return &h, nil
}
diff --git a/namespaces.go b/namespaces.go
index 9bbb6b32..9b8d1904 100644
--- a/namespaces.go
+++ b/namespaces.go
@@ -170,9 +170,8 @@ func (h *Headscale) checkForNamespacesPendingUpdates() {
}
for _, m := range *machines {
peers, _ := h.getPeers(m)
- h.pollMu.Lock()
for _, p := range *peers {
- pUp, ok := h.clientsPolling[uint64(p.ID)]
+ pUp, ok := h.clientsPolling.Load(uint64(p.ID))
if ok {
log.Info().
Str("func", "checkForNamespacesPendingUpdates").
@@ -180,7 +179,7 @@ func (h *Headscale) checkForNamespacesPendingUpdates() {
Str("peer", m.Name).
Str("address", p.Addresses[0].String()).
Msgf("Notifying peer %s (%s)", p.Name, p.Addresses[0])
- pUp <- []byte{}
+ pUp.(chan []byte) <- []byte{}
} else {
log.Info().
Str("func", "checkForNamespacesPendingUpdates").
@@ -189,7 +188,6 @@ func (h *Headscale) checkForNamespacesPendingUpdates() {
Msgf("Peer %s does not appear to be polling", p.Name)
}
}
- h.pollMu.Unlock()
}
}
newV, err := h.getValue("namespaces_pending_updates")
diff --git a/routes.go b/routes.go
index a02bed30..e188b91c 100644
--- a/routes.go
+++ b/routes.go
@@ -52,8 +52,8 @@ func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr
peers, _ := h.getPeers(*m)
h.pollMu.Lock()
for _, p := range *peers {
- if pUp, ok := h.clientsPolling[uint64(p.ID)]; ok {
- pUp <- []byte{}
+ if pUp, ok := h.clientsPolling.Load(uint64(p.ID)); ok {
+ pUp.(chan []byte) <- []byte{}
}
}
h.pollMu.Unlock()