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connection shutdown, channel close data race #196

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connection shutdown, channel close data race #196

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9831e04
safer and fail-faster reading of bogus frames
imkira Mar 28, 2016
f09251f
fix data race in connection shutdown and channel close
imkira Mar 28, 2016
524f95a
enforce wait for all goroutines in client tests
imkira Nov 29, 2016
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2 changes: 1 addition & 1 deletion .travis.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -11,4 +11,4 @@ services:
env:
- AMQP_URL=amqp://guest:guest@127.0.0.1:5672/ GOMAXPROCS=2

script: go test -v -tags integration ./...
script: go test -v -race -tags integration ./...
15 changes: 11 additions & 4 deletions channel.go
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Expand Up @@ -141,7 +141,11 @@ func (me *Channel) open() error {
// Performs a request/response call for when the message is not NoWait and is
// specified as Synchronous.
func (me *Channel) call(req message, res ...message) error {
if err := me.send(me, req); err != nil {
me.m.Lock()
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There is a separate mutex for sending stuff, me.sendM. I think we should use it here.

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@imkira imkira Nov 24, 2016 •
edited
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The original code is very misleading.
Please note that m.send starts as sendOpen and then switches to sendClosed:

https://github.com/imkira/amqp/blob/0563adcdb2a14308873fce26b14d3637dc2ac685/channel.go#L85
https://github.com/imkira/amqp/blob/0563adcdb2a14308873fce26b14d3637dc2ac685/channel.go#L104

Please, also note that each of those 2 functions use the mutex you specified for actually sending data.

What I am doing here is to protect a race condition that could happen if we used me.send directly.
That would collide with the following modification:

https://github.com/imkira/amqp/blob/0563adcdb2a14308873fce26b14d3637dc2ac685/channel.go#L104

send := me.send
me.m.Unlock()

if err := send(me, req); err != nil {
return err
}

Expand Down Expand Up @@ -273,22 +277,26 @@ func (me *Channel) dispatch(msg message) {
}

case *basicAck:
me.m.Lock()
if me.confirming {
if m.Multiple {
me.confirms.Multiple(Confirmation{m.DeliveryTag, true})
} else {
me.confirms.One(Confirmation{m.DeliveryTag, true})
}
}
me.m.Unlock()

case *basicNack:
me.m.Lock()
if me.confirming {
if m.Multiple {
me.confirms.Multiple(Confirmation{m.DeliveryTag, false})
} else {
me.confirms.One(Confirmation{m.DeliveryTag, false})
}
}
me.m.Unlock()

case *basicDeliver:
me.consumers.send(m.ConsumerTag, newDelivery(me, m))
Expand Down Expand Up @@ -1476,17 +1484,16 @@ exception could occur if the server does not support this method.

*/
func (me *Channel) Confirm(noWait bool) error {
me.m.Lock()
defer me.m.Unlock()

if err := me.call(
&confirmSelect{Nowait: noWait},
&confirmSelectOk{},
); err != nil {
return err
}

me.m.Lock()
me.confirming = true
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Bet advised - the me.confirming is also accessed:
https://github.com/streadway/amqp/blob/master/channel.go#L276
https://github.com/streadway/amqp/blob/master/channel.go#L285

Without any sort of mutex.

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@imkira imkira Nov 29, 2016 •
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Thanks for pointing out. I fixed it in c6a5ab1

me.m.Unlock()

return nil
}
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