net/http: panic: persistConn was already in LRU #18061
Comments
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Please build your program with the race detector and check that it contains
no data races.
…On Sun, Nov 27, 2016 at 10:34 PM, Zero ***@***.***> wrote:
What version of Go are you using (go version)?
go1.7.3
What operating system and processor architecture are you using (go env)?
Windows Server Standard 2007 SP2 32bit
panic: persistConn was already in LRU
goroutine 609111 [running]:
panic(0xa50dc0, 0x125a45d8)
/opt/dev/gopkg/go/src/runtime/panic.go:500 +0x331
net/http.(*connLRU).add(0x125de5b4, 0x1267c510)
/opt/dev/gopkg/go/src/net/http/transport.go:2147 +0x177
net/http.(*Transport).tryPutIdleConn(0x125de5a0, 0x1267c510, 0x0, 0x0)
/opt/dev/gopkg/go/src/net/http/transport.go:678 +0x5d8
net/http.(*persistConn).readLoop.func2(0x0, 0x125f2b01)
/opt/dev/gopkg/go/src/net/http/transport.go:1391 +0x32
net/http.(*persistConn).readLoop(0x1267c510)
/opt/dev/gopkg/go/src/net/http/transport.go:1548 +0xce1
created by net/http.(*Transport).dialConn
/opt/dev/gopkg/go/src/net/http/transport.go:1062 +0xda5
this is part of my code:
func DoRequest(/* som arguments */) {
// Very high frequency call code
var res *http.Response
err = nil
if r.Timeout > 0 {
err = errors.New("timeout")
c := make(chan *httpPeek)
go func() {
newRes, newErr := httpClient.Do(req)
select {
case c <- &httpPeek{newRes, newErr}:
default:
if newErr == nil && newRes != nil && newRes.Body != nil {
// Discard and close so we can reuse it
io.Copy(ioutil.Discard, newRes.Body)
newRes.Body.Close()
}
}
close(c)
}()
select {
case <-time.After(r.Timeout):
case v := <-c:
if v != nil {
res = v.res
err = v.err
}
}
} else {
res, err = httpClient.Do(req)
}
if err != nil {
return nil, err
}
// other code..
}
func init() {
timeout := time.Minute
httpClient = &http.Client{
Transport: &http.Transport{
MaxIdleConnsPerHost: 5,
TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
ResponseHeaderTimeout: timeout,
},
Timeout: timeout,
}
}
It's very hard to reproduce, program running about 20 hours, then panic
and exit !!
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bradfitz
changed the title
bradfitz
added
NeedsInvestigation
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I don't see how this can happen, but it also sounds disconcerting. Staring at the code, my best guess is it's something around cancelation, func (pc *persistConn) roundTrip(req *transportRequest) (resp *Response, err error) {
testHookEnterRoundTrip()
if !pc.t.replaceReqCanceler(req.Request, pc.cancelRequest) {
pc.t.putOrCloseIdleConn(pc)
return nil, errRequestCanceled
}And the Any help wanted. |
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The same thing happened again, I believe net/http library causing this bug. When I testing, I found a very strange question about map structure: func (ctx *SessionCtx) Handle(method uint8, handler func([]byte) []byte) {
ctx.mutex.Lock()
ctx.dispatcher[method] = handler
ctx.mutex.Unlock()
}I put a method when init this Session: ctx.Handle(TID_Ping, somefunc)but I never change or deleted this key in map, In a high frequency code block like: func (ctx *SessionCtx) OnPing() {
ctx.mutex.Lock()
handler, ok := ctx.dispatcher[TID_Ping]
ctx.mutex.Unlock()
// running some days, ok return is false !!!, but I never delete this key, GC's BUG ??
}program running some days, something strange happen, ok return false, means not found the key, But I never deleted this key after I insert to the map, Is GC's bug ?? I think the problem might be related to the net/http problem Test ENV: Windows Server Standard 2007 SP2 32bit |
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@botvs, sorry, I don't understand. Could you please answer @davecheney's question first? Have you run your program under the race detector? https://blog.golang.org/race-detector |
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@bradfitz I'm starting to test with race-detector now. |
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@bradfitz bug triggered only in windows 32bit. |
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Sorry. You'll have to use a 64-bit OS to run the race detector. Maybe you can test on a cloud VM or something if you can't install a 64-bit OS on your machine. (I imagine your machine is actually a 64-bit processor) I'm going to close this bug for now since there's nothing actionable for us at the moment. I can't find a path in the code where this can happen and without a repro I can't debug further. Let's move conversation to https://golang.org/wiki/Questions until there's something concrete for us to fix. |
What version of Go are you using (
go version)?go1.7.3
What operating system and processor architecture are you using (
go env)?Windows Server Standard 2007 SP2 32bit
this is part of my code:
It's very hard to reproduce, program running about 20 hours, then panic and exit !!
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