Fix DNS cache lock goroutine leak

The cache deduplication in Client.Exchange uses a channel-based lock
per DNS question. Waiting goroutines blocked on <-cond without context
awareness, causing them to accumulate indefinitely when the owning
goroutine's transport call stalls. Add select on ctx.Done() so waiters
respect context cancellation and timeouts.
This commit is contained in:
世界
2026-02-06 22:28:30 +08:00
parent 6177981707
commit 264e7ad3ee

View File

@@ -144,7 +144,11 @@ func (c *Client) Exchange(ctx context.Context, transport adapter.DNSTransport, m
if c.cache != nil {
cond, loaded := c.cacheLock.LoadOrStore(question, make(chan struct{}))
if loaded {
<-cond
select {
case <-cond:
case <-ctx.Done():
return nil, ctx.Err()
}
} else {
defer func() {
c.cacheLock.Delete(question)
@@ -154,7 +158,11 @@ func (c *Client) Exchange(ctx context.Context, transport adapter.DNSTransport, m
} else if c.transportCache != nil {
cond, loaded := c.transportCacheLock.LoadOrStore(question, make(chan struct{}))
if loaded {
<-cond
select {
case <-cond:
case <-ctx.Done():
return nil, ctx.Err()
}
} else {
defer func() {
c.transportCacheLock.Delete(question)