Crash from unknown cause

[jhchabran]

I got this crash while toying with graph libraries. On client-side the only thing I added was a handler which supposedly don't do anything that could crash it. I refreshed the page really often while editing code, which opens the websocket, if that can help.

Trace:

 (master) ~/go/src/github.com/openflylab/bridge$ sudo ./bridge -port 3000 uavobjectdefinition/
2015/06/29 12:29:24 Websocket server started on port 3000
2015/06/29 12:29:26 Connection received
2015/06/29 12:29:26 Treating messages
2015/06/29 12:29:26 Starting HID
2015/06/29 12:30:53 EOF
2015/06/29 12:30:53 websocket: close sent
2015/06/29 12:30:53 Closing <- HID goroutine
2015/06/29 12:30:53 Closing HID
2015/06/29 12:30:53 Closing -> HID goroutine
2015/06/29 12:30:53 Connection received
2015/06/29 12:30:53 Treating messages
2015/06/29 12:30:53 Starting HID
2015/06/29 12:31:38 EOF
2015/06/29 12:31:38 websocket: close sent
2015/06/29 12:31:38 Closing <- HID goroutine
2015/06/29 12:31:38 Closing HID
2015/06/29 12:31:38 Closing -> HID goroutine
2015/06/29 12:31:38 Connection received
2015/06/29 12:31:38 Treating messages
2015/06/29 12:31:38 Starting HID
2015/06/29 12:31:59 EOF
2015/06/29 12:31:59 Connection received
2015/06/29 12:31:59 Treating messages
2015/06/29 12:31:59 websocket: close sent
2015/06/29 12:31:59 Closing <- HID goroutine
2015/06/29 12:31:59 Closing HID
2015/06/29 12:31:59 Closing -> HID goroutine
^C (master) ~/go/src/github.com/openflylab/bridge$ sudo ./bridge -port 3000 uavobjectdefinition/
2015/06/29 12:32:22 Websocket server started on port 3000
2015/06/29 12:32:29 Connection received
2015/06/29 12:32:29 Treating messages
2015/06/29 12:32:39 EOF
2015/06/29 12:32:39 Connection received
2015/06/29 12:32:39 Treating messages
2015/06/29 12:32:40 Starting HID
panic:

goroutine 16 [running]:
runtime.panic(0x658620, 0xc210168740)
        /usr/lib/go/src/pkg/runtime/panic.c:266 +0xb6
main.func·002()
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:235 +0x416
created by main.startHID
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:240 +0x3db

goroutine 1 [select (no cases)]:
main.main()
        /home/tech/go/src/github.com/openflylab/bridge/main.go:25 +0x28e

goroutine 3 [syscall]:
runtime.goexit()
        /usr/lib/go/src/pkg/runtime/proc.c:1394

goroutine 4 [finalizer wait]:
runtime.park(0x416210, 0xb9a1c0, 0xb85fa8)
        /usr/lib/go/src/pkg/runtime/proc.c:1342 +0x66
runfinq()
        /usr/lib/go/src/pkg/runtime/mgc0.c:2279 +0x84
runtime.goexit()
        /usr/lib/go/src/pkg/runtime/proc.c:1394

goroutine 5 [chan receive]:
main.func·003()
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:261 +0x74
created by main.startUAVTalk
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:274 +0x8b

goroutine 6 [IO wait]:
net.runtime_pollWait(0x7ff868d24678, 0x72, 0x0)
        /usr/lib/go/src/pkg/runtime/netpoll.goc:116 +0x6a
net.(*pollDesc).Wait(0xc210174ed0, 0x72, 0x7ff868d1d0e8, 0xb)
        /usr/lib/go/src/pkg/net/fd_poll_runtime.go:81 +0x34
net.(*pollDesc).WaitRead(0xc210174ed0, 0xb, 0x7ff868d1d0e8)
        /usr/lib/go/src/pkg/net/fd_poll_runtime.go:86 +0x30
net.(*netFD).accept(0xc210174e70, 0x744480, 0x0, 0x7ff868d1d0e8, 0xb)
        /usr/lib/go/src/pkg/net/fd_unix.go:382 +0x2c2
net.(*TCPListener).AcceptTCP(0xc2101463b0, 0x4a981b, 0x7ff868ba5e78, 0x4a981b)
        /usr/lib/go/src/pkg/net/tcpsock_posix.go:233 +0x47
net.(*TCPListener).Accept(0xc2101463b0, 0x7ff868d24720, 0xc210146ad0, 0xc21015b100, 0x0)
        /usr/lib/go/src/pkg/net/tcpsock_posix.go:243 +0x27
net/http.(*Server).Serve(0xc21014fd20, 0x7ff868d236d8, 0xc2101463b0, 0x0, 0x0)
        /usr/lib/go/src/pkg/net/http/server.go:1622 +0x91
net/http.(*Server).ListenAndServe(0xc21014fd20, 0xc21014fd20, 0x0)
        /usr/lib/go/src/pkg/net/http/server.go:1612 +0xa0
net/http.ListenAndServe(0xc2101462e0, 0x5, 0x0, 0x0, 0x1, ...)
        /usr/lib/go/src/pkg/net/http/server.go:1677 +0x6d
created by main.startAsServer
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:124 +0x1c1

goroutine 7 [semacquire]:
sync.runtime_Semacquire(0xc210146988)
        /usr/lib/go/src/pkg/runtime/sema.goc:199 +0x30
sync.(*WaitGroup).Wait(0xc210147b80)
        /usr/lib/go/src/pkg/sync/waitgroup.go:127 +0x14b
main.func·007(0x7ff868d24878, 0xc21000f0a0, 0xc2100590d0)
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:121 +0x423
net/http.HandlerFunc.ServeHTTP(0xc210147300, 0x7ff868d24878, 0xc21000f0a0, 0xc2100590d0)
        /usr/lib/go/src/pkg/net/http/server.go:1220 +0x40
net/http.(*ServeMux).ServeHTTP(0xc21001e660, 0x7ff868d24878, 0xc21000f0a0, 0xc2100590d0)
        /usr/lib/go/src/pkg/net/http/server.go:1496 +0x163
net/http.serverHandler.ServeHTTP(0xc21014fd20, 0x7ff868d24878, 0xc21000f0a0, 0xc2100590d0)
        /usr/lib/go/src/pkg/net/http/server.go:1597 +0x16e
net/http.(*conn).serve(0xc21015bd80)
        /usr/lib/go/src/pkg/net/http/server.go:1167 +0x7b7
created by net/http.(*Server).Serve
        /usr/lib/go/src/pkg/net/http/server.go:1644 +0x28b

goroutine 8 [chan receive]:
main.startHID(0xc210038f60, 0xc21017cc00, 0xc21017c000)
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:242 +0x3f7
created by main.func·003
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:264 +0xcd

goroutine 9 [chan receive]:
main.func·005()
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:48 +0x76
created by main.func·007
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:75 +0x311

goroutine 12 [semacquire]:
sync.runtime_Semacquire(0xc210146b70)
        /usr/lib/go/src/pkg/runtime/sema.goc:199 +0x30
sync.(*WaitGroup).Wait(0xc210147e60)
        /usr/lib/go/src/pkg/sync/waitgroup.go:127 +0x14b
main.func·007(0x7ff868d24878, 0xc21011e1e0, 0xc210059340)
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:121 +0x423
net/http.HandlerFunc.ServeHTTP(0xc210147300, 0x7ff868d24878, 0xc21011e1e0, 0xc210059340)
        /usr/lib/go/src/pkg/net/http/server.go:1220 +0x40
net/http.(*ServeMux).ServeHTTP(0xc21001e660, 0x7ff868d24878, 0xc21011e1e0, 0xc210059340)
        /usr/lib/go/src/pkg/net/http/server.go:1496 +0x163
net/http.serverHandler.ServeHTTP(0xc21014fd20, 0x7ff868d24878, 0xc21011e1e0, 0xc210059340)
        /usr/lib/go/src/pkg/net/http/server.go:1597 +0x16e
net/http.(*conn).serve(0xc21015b100)
        /usr/lib/go/src/pkg/net/http/server.go:1167 +0x7b7
created by net/http.(*Server).Serve
        /usr/lib/go/src/pkg/net/http/server.go:1644 +0x28b

goroutine 13 [chan receive]:
main.func·005()
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:48 +0x76
created by main.func·007
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:75 +0x311

goroutine 14 [IO wait]:
net.runtime_pollWait(0x7ff868d24528, 0x72, 0x0)
        /usr/lib/go/src/pkg/runtime/netpoll.goc:116 +0x6a
net.(*pollDesc).Wait(0xc2101674c0, 0x72, 0x7ff868d1d0e8, 0xb)
        /usr/lib/go/src/pkg/net/fd_poll_runtime.go:81 +0x34
net.(*pollDesc).WaitRead(0xc2101674c0, 0xb, 0x7ff868d1d0e8)
        /usr/lib/go/src/pkg/net/fd_poll_runtime.go:86 +0x30
net.(*netFD).Read(0xc210167460, 0xc21016f000, 0x800, 0x800, 0x0, ...)
        /usr/lib/go/src/pkg/net/fd_unix.go:204 +0x2a0
net.(*conn).Read(0xc210146ad0, 0xc21016f000, 0x800, 0x800, 0x604c40, ...)
        /usr/lib/go/src/pkg/net/net.go:122 +0xc5
bufio.(*Reader).fill(0xc21015fd20)
        /usr/lib/go/src/pkg/bufio/bufio.go:91 +0x110
bufio.(*Reader).Read(0xc21015fd20, 0xc210146c58, 0x2, 0x8, 0x2, ...)
        /usr/lib/go/src/pkg/bufio/bufio.go:159 +0x1a4
github.com/gorilla/websocket.(*Conn).readFull(0xc21014e1e0, 0xc210146c58, 0x2, 0x8, 0x0, ...)
        /home/tech/go/src/github.com/gorilla/websocket/conn.go:542 +0xac
github.com/gorilla/websocket.(*Conn).advanceFrame(0xc21014e1e0, 0x41034c, 0x5f8b20, 0xc21017c000)
        /home/tech/go/src/github.com/gorilla/websocket/conn.go:566 +0x12b
github.com/gorilla/websocket.(*Conn).NextReader(0xc21014e1e0, 0xc21017c000, 0x0, 0x0, 0x0, ...)
        /home/tech/go/src/github.com/gorilla/websocket/conn.go:706 +0x67
main.func·006()
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:82 +0x66
created by main.func·007
        /home/tech/go/src/github.com/openflylab/bridge/uavwebsocket.go:118 +0x367

goroutine 15 [syscall]:
github.com/GeertJohan/go%2ehid._Cfunc_hid_read(0x1b11a40, 0xc21014cf00, 0x40, 0x0)
        github.com/GeertJohan/go.hid/_obj/_cgo_defun.c:169 +0x31
github.com/GeertJohan/go%2ehid.(*Device).Read(0xc210146c60, 0xc21014cf00, 0x40, 0x40, 0x0, ...)
        /home/tech/go/src/github.com/GeertJohan/go.hid/hid.go:440 +0x81
main.func·001()
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:189 +0x22a
created by main.startHID
        /home/tech/go/src/github.com/openflylab/bridge/uavtalk.go:214 +0x361

[vitaminwater]

Stinks like a race condition... the thing is that it tried to write on the USB connection after it had been closed.

Are you sure you weren't sending anything ?

[jhchabran]

You're right, I was sending GcsTelemetryStats UAV as it's always done when connecting. Makes more sense now :)