globalsign/mgo: panic

[kokizzu]

I've tried connection string (from Go) with nodejs and it works successfully (after escaping the password):

    const {MongoClient} = require('mongodb');
    (new MongoClient('mongodb://rwuser:1vK6c6%7Dc24Rr%28%2A%[email protected].:27017/mongodbtest1?connectTimeoutMS=1000&wtimeoutMS=1000')).connect()

but when I tried the exact connection string, which is generated from this code:

    func (c ConnectOption) ToUrl() string {
      ms := timeout.Milliseconds()
	  res := fmt.Sprintf("mongodb://%s:%s@%s/%s?connectTimeoutMS=%d&wtimeoutMS=%d", 
        c.Username, url.QueryEscape(c.Password), c.Hosts, c.DBName, ms, ms)
      return res
    }

it shows exact same error error as when the password not escaped:

     panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x80 pc=0x8dd963]
    goroutine 1 [running]:
    sync.(*RWMutex).RLock(...)
        /usr/local/go/src/sync/rwmutex.go:48
    github.com/globalsign/mgo.(*Session).acquireSocket(0x0, 0x42ed01, 0x0, 0x0, 0x0)
        /go/pkg/mod/github.com/globalsign/[email protected]/session.go:5101 +0x53
    github.com/globalsign/mgo.(*Database).Run(0xc00074d868, 0xb912c0, 0xc00072c4a0, 0xb866c0, 0xc00016a230, 0x0, 0x0)
        /go/pkg/mod/github.com/globalsign/[email protected]/session.go:992 +0x53
    github.com/globalsign/mgo.(*Session).Run(0x0, 0xb912c0, 0xc00072c4a0, 0xb866c0, 0xc00016a230, 0xc0001965a0, 0xc00074d918)
        /go/pkg/mod/github.com/globalsign/[email protected]/session.go:2489 +0x8a
    github.com/globalsign/mgo.(*Session).BuildInfo(0x0, 0xb7, 0x0, 0xd95b40, 0xc0001965a0, 0x203000, 0x203000, 0x203000, 0x0, 0xc00074da80, ...)
        /go/pkg/mod/github.com/globalsign/[email protected]/session.go:5071 +0x101
    gopkg.in/DataDog/dd-trace-go.v1/contrib/globalsign/mgo.Dial(0xc000758000, 0xb7, 0xc00074db18, 0x2, 0x2, 0xc00002634c, 0xd, 0xc0000262cc)
        /go/pkg/mod/gopkg.in/!data!dog/[email protected]/contrib/globalsign/mgo/mgo.go:25 +0x80
    dummyproject/testmongo1/database/mongodb.Client(0xc00002205e, 0x39, 0xc00002a128, 0x22, 0x0, 0xc00002634c, 0xd, 0xc0000262cc, 0x14, 0xc00074dc00, ...)
        /go/src/dummyproject/testmongo1/database/mongodb/mongodb.go:67 +0x14c
    dummyproject/testmongo1/database/mongodb.DBFromEnv(0xc8050f)
        /go/src/dummyproject/testmongo1/database/mongodb/mongodb.go:155 +0x1dc
    dummyproject/testmongo1/database.InitDatabase()
        /go/src/dummyproject/testmongo1/database/database.go:15 +0xa4
    dummyproject/testmongo1.Newtestmongo1(0xc00074ded8)
        /go/src/dummyproject/testmongo1/testmongo1.go:43 +0x177
    main.main()
        /go/src/dummyproject/testmongo1/app/web/main.go:24 +0x8a

It runs on alpine docker, what's the other possible cause?

The lines testmongo1/database/mongodb/mongodb.go:67 are:

    session, err := mgo.Dial(opt.ToUrl(timeout()), 
        mgo.WithServiceName(`cinderella-mongo`),
		mgo.WithAnalytics(true))

mgo is a package, opt is not nil, timeout() returns concrete time.Duration, so there's no way that it's that line's that causes the error.

[gbbr]

Have you tried posting this issue on the globalsign/mgo repository? Based on the stack trace it seems like the problem is coming from there...

[knusbaum]

@kokizzu

Based on your trace, I believe I see that we're calling BuildInfo on a nil mgo.(*Session) object on this line

It looks like we don't check the err return before using the *Session.

    github.com/globalsign/mgo.(*Session).BuildInfo(0x0, 0xb7, 0x0, 0xd95b40, 0xc0001965a0, 0x203000, 0x203000, 0x203000, 0x0, 0xc00074da80, ...)
        /go/pkg/mod/github.com/globalsign/[email protected]/session.go:5071 +0x101