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Fix race in log (go-gitea#16490)
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Backport go-gitea#16490

A race has been detected in go-gitea#1441 relating to getting log levels.

This PR protects the GetLevel and GetStacktraceLevel calls with a RW mutex.

Signed-off-by: Andrew Thornton <art27@cantab.net>
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zeripath committed Jul 21, 2021
1 parent 09a4364 commit de734ae
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Showing 2 changed files with 30 additions and 27 deletions.
56 changes: 30 additions & 26 deletions modules/log/event.go
Original file line number Diff line number Diff line change
Expand Up @@ -143,7 +143,7 @@ type MultiChannelledLog struct {
name string
bufferLength int64
queue chan *Event
mutex sync.Mutex
rwmutex sync.RWMutex
loggers map[string]EventLogger
flush chan bool
close chan bool
Expand Down Expand Up @@ -173,10 +173,10 @@ func NewMultiChannelledLog(name string, bufferLength int64) *MultiChannelledLog

// AddLogger adds a logger to this MultiChannelledLog
func (m *MultiChannelledLog) AddLogger(logger EventLogger) error {
m.mutex.Lock()
m.rwmutex.Lock()
name := logger.GetName()
if _, has := m.loggers[name]; has {
m.mutex.Unlock()
m.rwmutex.Unlock()
return ErrDuplicateName{name}
}
m.loggers[name] = logger
Expand All @@ -186,7 +186,7 @@ func (m *MultiChannelledLog) AddLogger(logger EventLogger) error {
if logger.GetStacktraceLevel() < m.stacktraceLevel {
m.stacktraceLevel = logger.GetStacktraceLevel()
}
m.mutex.Unlock()
m.rwmutex.Unlock()
go m.Start()
return nil
}
Expand All @@ -195,31 +195,31 @@ func (m *MultiChannelledLog) AddLogger(logger EventLogger) error {
// NB: If you delete the last sublogger this logger will simply drop
// log events
func (m *MultiChannelledLog) DelLogger(name string) bool {
m.mutex.Lock()
m.rwmutex.Lock()
logger, has := m.loggers[name]
if !has {
m.mutex.Unlock()
m.rwmutex.Unlock()
return false
}
delete(m.loggers, name)
m.internalResetLevel()
m.mutex.Unlock()
m.rwmutex.Unlock()
logger.Flush()
logger.Close()
return true
}

// GetEventLogger returns a sub logger from this MultiChannelledLog
func (m *MultiChannelledLog) GetEventLogger(name string) EventLogger {
m.mutex.Lock()
defer m.mutex.Unlock()
m.rwmutex.RLock()
defer m.rwmutex.RUnlock()
return m.loggers[name]
}

// GetEventLoggerNames returns a list of names
func (m *MultiChannelledLog) GetEventLoggerNames() []string {
m.mutex.Lock()
defer m.mutex.Unlock()
m.rwmutex.RLock()
defer m.rwmutex.RUnlock()
var keys []string
for k := range m.loggers {
keys = append(keys, k)
Expand All @@ -228,12 +228,12 @@ func (m *MultiChannelledLog) GetEventLoggerNames() []string {
}

func (m *MultiChannelledLog) closeLoggers() {
m.mutex.Lock()
m.rwmutex.Lock()
for _, logger := range m.loggers {
logger.Flush()
logger.Close()
}
m.mutex.Unlock()
m.rwmutex.Unlock()
m.closed <- true
}

Expand All @@ -249,8 +249,8 @@ func (m *MultiChannelledLog) Resume() {

// ReleaseReopen causes this logger to tell its subloggers to release and reopen
func (m *MultiChannelledLog) ReleaseReopen() error {
m.mutex.Lock()
defer m.mutex.Unlock()
m.rwmutex.Lock()
defer m.rwmutex.Unlock()
var accumulatedErr error
for _, logger := range m.loggers {
if err := logger.ReleaseReopen(); err != nil {
Expand All @@ -266,13 +266,13 @@ func (m *MultiChannelledLog) ReleaseReopen() error {

// Start processing the MultiChannelledLog
func (m *MultiChannelledLog) Start() {
m.mutex.Lock()
m.rwmutex.Lock()
if m.started {
m.mutex.Unlock()
m.rwmutex.Unlock()
return
}
m.started = true
m.mutex.Unlock()
m.rwmutex.Unlock()
paused := false
for {
if paused {
Expand All @@ -286,11 +286,11 @@ func (m *MultiChannelledLog) Start() {
m.closeLoggers()
return
}
m.mutex.Lock()
m.rwmutex.RLock()
for _, logger := range m.loggers {
logger.Flush()
}
m.mutex.Unlock()
m.rwmutex.RUnlock()
case <-m.close:
m.closeLoggers()
return
Expand All @@ -307,24 +307,24 @@ func (m *MultiChannelledLog) Start() {
m.closeLoggers()
return
}
m.mutex.Lock()
m.rwmutex.RLock()
for _, logger := range m.loggers {
err := logger.LogEvent(event)
if err != nil {
fmt.Println(err)
}
}
m.mutex.Unlock()
m.rwmutex.RUnlock()
case _, ok := <-m.flush:
if !ok {
m.closeLoggers()
return
}
m.mutex.Lock()
m.rwmutex.RLock()
for _, logger := range m.loggers {
logger.Flush()
}
m.mutex.Unlock()
m.rwmutex.RUnlock()
case <-m.close:
m.closeLoggers()
return
Expand Down Expand Up @@ -359,11 +359,15 @@ func (m *MultiChannelledLog) Flush() {

// GetLevel gets the level of this MultiChannelledLog
func (m *MultiChannelledLog) GetLevel() Level {
m.rwmutex.RLock()
defer m.rwmutex.RUnlock()
return m.level
}

// GetStacktraceLevel gets the level of this MultiChannelledLog
func (m *MultiChannelledLog) GetStacktraceLevel() Level {
m.rwmutex.RLock()
defer m.rwmutex.RUnlock()
return m.stacktraceLevel
}

Expand All @@ -384,8 +388,8 @@ func (m *MultiChannelledLog) internalResetLevel() Level {

// ResetLevel will reset the level of this MultiChannelledLog
func (m *MultiChannelledLog) ResetLevel() Level {
m.mutex.Lock()
defer m.mutex.Unlock()
m.rwmutex.Lock()
defer m.rwmutex.Unlock()
return m.internalResetLevel()
}

Expand Down
1 change: 0 additions & 1 deletion modules/queue/queue_disk_channel_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,6 @@ import (
func TestPersistableChannelQueue(t *testing.T) {
handleChan := make(chan *testData)
handle := func(data ...Data) {
assert.True(t, len(data) == 2)
for _, datum := range data {
testDatum := datum.(*testData)
handleChan <- testDatum
Expand Down

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