App panic on concurrent map writes (0aaacc2)

[errordeveloper]

goroutine 2010 [running]:
runtime.throw(0x18221a0, 0x15)
    /usr/local/go/src/runtime/panic.go:530 +0x90 fp=0xc824c05480 sp=0xc824c05468
runtime.mapassign1(0x15d4e00, 0xc824b52240, 0xc824c05638, 0xc824c05ac8)
    /usr/local/go/src/runtime/hashmap.go:445 +0xb1 fp=0xc824c05528 sp=0xc824c05480
github.com/weaveworks/scope/render.containerWithImageNameRenderer.Render(0x7f8e099a1830, 0xc820399910, 0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, ...)
    /go/src/github.com/weaveworks/scope/render/topologies.go:189 +0x3a8 fp=0xc824c05c30 sp=0xc824c05528
github.com/weaveworks/scope/render.(*containerWithImageNameRenderer).Render(0xc820384ce0, 0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, 0xc8223337a0, ...)
    <autogenerated>:68 +0xbb fp=0xc824c05d10 sp=0xc824c05c30
github.com/weaveworks/scope/render.(*Filter).render(0xc825a46020, 0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, 0xc8223337a0, ...)
    /go/src/github.com/weaveworks/scope/render/filters.go:78 +0xee fp=0xc824c069e0 sp=0xc824c05d10
github.com/weaveworks/scope/render.(*Filter).Render(0xc825a46020, 0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, 0xc8223337a0, ...)
    /go/src/github.com/weaveworks/scope/render/filters.go:70 +0x3e fp=0xc824c06ac0 sp=0xc824c069e0
github.com/weaveworks/scope/render.(*memoise).Render(0xc825a46060, 0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, 0xc8223337a0, ...)
    /go/src/github.com/weaveworks/scope/render/memoise.go:35 +0x2c4 fp=0xc824c06c40 sp=0xc824c06ac0
github.com/weaveworks/scope/app.decorateWithStats(0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, 0xc8223337a0, 0xc822bc4300, ...)
    /go/src/github.com/weaveworks/scope/app/api_topologies.go:223 +0x94 fp=0xc824c07050 sp=0xc824c06c40
github.com/weaveworks/scope/app.(*registry).renderTopologies.func1(0x174ed30, 0xa, 0x0, 0x0, 0x7f8e099a1908, 0xc820384ce0, 0x1740060, 0xa, 0x2, 0xc8202f7bc0, ...)
    /go/src/github.com/weaveworks/scope/app/api_topologies.go:207 +0xa8 fp=0xc824c071c0 sp=0xc824c07050
github.com/weaveworks/scope/app.(*registry).walk(0x23691c0, 0xc824c075a8)
    /go/src/github.com/weaveworks/scope/app/api_topologies.go:191 +0x2bc fp=0xc824c07580 sp=0xc824c071c0
github.com/weaveworks/scope/app.(*registry).renderTopologies(0x23691c0, 0xc8210f4090, 0xc82526dd40, 0xc82526dd70, 0xc824c295f0, 0xc824c29620, 0xc824c25bc0, 0xc824c25e00, 0xc82247fe60, 0xc8223337a0, ...)
    /go/src/github.com/weaveworks/scope/app/api_topologies.go:213 +0xa7 fp=0xc824c075d0 sp=0xc824c07580
github.com/weaveworks/scope/app.(*registry).makeTopologyList.func1(0x7f8e0812e410, 0xc821156450, 0x7f8e0812e398, 0xc822f38580, 0xc8201269a0)
    /go/src/github.com/weaveworks/scope/app/api_topologies.go:198 +0xb5 fp=0xc824c077c8 sp=0xc824c075d0
github.com/weaveworks/scope/app.requestContextDecorator.func1(0x7f8e0812e398, 0xc822f38580, 0xc8201269a0)
    /go/src/github.com/weaveworks/scope/app/router.go:37 +0x226 fp=0xc824c078b0 sp=0xc824c077c8
net/http.HandlerFunc.ServeHTTP(0xc820377270, 0x7f8e0812e398, 0xc822f38580, 0xc8201269a0)
    /usr/local/go/src/net/http/server.go:1618 +0x3a fp=0xc824c078d0 sp=0xc824c078b0
github.com/weaveworks/scope/vendor/github.com/PuerkitoBio/ghost/handlers.GZIPHandler.func1(0x7f8e0812e280, 0xc8201a2270, 0xc8201269a0)
    /go/src/github.com/weaveworks/scope/vendor/github.com/PuerkitoBio/ghost/handlers/gzip.go:127 +0x330 fp=0xc824c07968 sp=0xc824c078d0
net/http.HandlerFunc.ServeHTTP(0xc8203dae40, 0x7f8e0812e280, 0xc8201a2270, 0xc8201269a0)
    /usr/local/go/src/net/http/server.go:1618 +0x3a fp=0xc824c07988 sp=0xc824c07968
github.com/weaveworks/scope/vendor/github.com/gorilla/mux.(*Router).ServeHTTP(0xc8203d8280, 0x7f8e0812e280, 0xc8201a2270, 0xc8201269a0)
    /go/src/github.com/weaveworks/scope/vendor/github.com/gorilla/mux/mux.go:100 +0x29e fp=0xc824c07aa0 sp=0xc824c07988
github.com/weaveworks/scope/app.TopologyHandler.func1(0x7f8e0812e280, 0xc8201a2270, 0xc8201269a0)
    /go/src/github.com/weaveworks/scope/app/router.go:113 +0xa7 fp=0xc824c07b30 sp=0xc824c07aa0
net/http.HandlerFunc.ServeHTTP(0xc8203db660, 0x7f8e0812e280, 0xc8201a2270, 0xc8201269a0)
    /usr/local/go/src/net/http/server.go:1618 +0x3a fp=0xc824c07b50 sp=0xc824c07b30
net/http.serverHandler.ServeHTTP(0xc820088c00, 0x7f8e0812e280, 0xc8201a2270, 0xc8201269a0)
    /usr/local/go/src/net/http/server.go:2081 +0x19e fp=0xc824c07bb0 sp=0xc824c07b50
net/http.(*conn).serve(0xc820088880)
    /usr/local/go/src/net/http/server.go:1472 +0xf2e fp=0xc824c07f78 sp=0xc824c07bb0
runtime.goexit()
    /usr/local/go/src/runtime/asm_amd64.s:1998 +0x1 fp=0xc824c07f80 sp=0xc824c07f78
created by net/http.(*Server).Serve
    /usr/local/go/src/net/http/server.go:2137 +0x44e

[2opremio]

It's crashing here

scope/render/topologies.go

Line 189 in 0aaacc2

containers[id] = c

And it seems that Go 1.6 is panicking after detecting a race:

$ docker run golang:1.6.0 sed -n '445p' /usr/local/go/src/runtime/hashmap.go 
                throw("concurrent map writes")

Here's a longer excerpt of the code

func mapassign1(t *maptype, h *hmap, key unsafe.Pointer, val unsafe.Pointer) {
        if h == nil {
                panic("assignment to entry in nil map")
        }
        if raceenabled {
                callerpc := getcallerpc(unsafe.Pointer(&t))
                pc := funcPC(mapassign1)
                racewritepc(unsafe.Pointer(h), callerpc, pc)
                raceReadObjectPC(t.key, key, callerpc, pc)
                raceReadObjectPC(t.elem, val, callerpc, pc)
        }
        if msanenabled {
                msanread(key, t.key.size)
                msanread(val, t.elem.size)
        }
        if h.flags&hashWriting != 0 {
                throw("concurrent map writes")
        }
        h.flags |= hashWriting

        alg := t.key.alg
        hash := alg.hash(key, uintptr(h.hash0))

        if h.buckets == nil {
                h.buckets = newarray(t.bucket, 1)
        }

[2opremio]

@errordeveloper Can you please paste a gist with the full backtrace (i.e. including all the goroutines). I believe it will reveal who is accessing the map concurrently.

[errordeveloper]

Full logs.

[paulbellamy]

Probably a duplicate of #1087