Data method is not thread safe. about stats

[thoas]

could you add some tests on this?

[e-max]

I am not sure how to make this tests not so ugly )
#14

[e-max]

It cause panic only if use go 1.6. I am not sure how to test it on previous versions.

[heu]

It seem that the returns of Data() function include the maps (references) from Stats structure, any further access to those maps is not protected by RWMutex (privated in Stats)

[emilevauge]

Hi!
Any news on this?
I'm also having this issue on traefik traefik/traefik#458.
We are getting this error while json encoding the Data struct:

fatal error: concurrent map read and map write

goroutine 6569 [running]:
runtime.throw(0x10932c0, 0x21)
        /usr/local/go/src/runtime/panic.go:547 +0x90 fp=0xc8213b1128 sp=0xc8213b1110
runtime.mapaccess2(0xc27f20, 0xc8202a99b0, 0xc82000bb10, 0x3, 0x6c7d9e)
        /usr/local/go/src/runtime/hashmap.go:343 +0x5a fp=0xc8213b1170 sp=0xc8213b1128
reflect.mapaccess(0xc27f20, 0xc8202a99b0, 0xc82000bb10, 0xc8202a99b0)
        /usr/local/go/src/runtime/hashmap.go:993 +0x35 fp=0xc8213b11a0 sp=0xc8213b1170
reflect.Value.MapIndex(0xc27f20, 0xc830c04160, 0x195, 0xc2caa0, 0xc82000bb10, 0x98, 0x0, 0x0, 0x0)
        /usr/local/go/src/reflect/value.go:1041 +0x14a fp=0xc8213b1228 sp=0xc8213b11a0
encoding/json.(*mapEncoder).encode(0xc825a10310, 0xc8306c00b0, 0xc27f20, 0xc830c04160, 0x195, 0x0)
        /usr/local/go/src/encoding/json/encode.go:622 +0x2ec fp=0xc8213b1318 sp=0xc8213b1228
encoding/json.(*mapEncoder).(encoding/json.encode)-fm(0xc8306c00b0, 0xc27f20, 0xc830c04160, 0x195, 0x0)
        /usr/local/go/src/encoding/json/encode.go:632 +0x51 fp=0xc8213b1350 sp=0xc8213b1318
encoding/json.(*structEncoder).encode(0xc8258dcb40, 0xc8306c00b0, 0xf2a9a0, 0xc830c04120, 0x199, 0x0)
        /usr/local/go/src/encoding/json/encode.go:587 +0x2c4 fp=0xc8213b14f8 sp=0xc8213b1350
encoding/json.(*structEncoder).(encoding/json.encode)-fm(0xc8306c00b0, 0xf2a9a0, 0xc830c04120, 0x199, 0xc830c04100)
        /usr/local/go/src/encoding/json/encode.go:601 +0x51 fp=0xc8213b1530 sp=0xc8213b14f8
encoding/json.(*ptrEncoder).encode(0xc825a10350, 0xc8306c00b0, 0xbd76a0, 0xc830c04120, 0x16, 0x0)
        /usr/local/go/src/encoding/json/encode.go:709 +0xea fp=0xc8213b1580 sp=0xc8213b1530
encoding/json.(*ptrEncoder).(encoding/json.encode)-fm(0xc8306c00b0, 0xbd76a0, 0xc830c04120, 0x16, 0xc830c04100)
        /usr/local/go/src/encoding/json/encode.go:714 +0x51 fp=0xc8213b15b8 sp=0xc8213b1580
encoding/json.(*encodeState).reflectValue(0xc8306c00b0, 0xbd76a0, 0xc830c04120, 0x16)
        /usr/local/go/src/encoding/json/encode.go:301 +0x6b fp=0xc8213b15e8 sp=0xc8213b15b8
encoding/json.(*encodeState).marshal(0xc8306c00b0, 0xbd76a0, 0xc830c04120, 0x0, 0x0)
        /usr/local/go/src/encoding/json/encode.go:274 +0xa9 fp=0xc8213b1630 sp=0xc8213b15e8
encoding/json.Marshal(0xbd76a0, 0xc830c04120, 0x0, 0x0, 0x0, 0x0, 0x0)

[emilevauge]

Ping @thoas :)

[thoas]

will look into this, you can send me a PR if you want :)

[thoas]

fixed

[thoas]

reopening still not fixed

[thoas]

fixed in master