Reconnect hangs silently

[bkero]

Whenever my bot disconnects from an IRC network (irc.cat.pdx.edu) due to the following error:

2020/05/23 00:04:06 Error, disconnected: read tcp 192.168.42.50:51854->131.252.208.26:6697: i/o timeout
2020/05/23 00:04:07 Connected to irc.cat.pdx.edu:6697 (131.252.208.26:6697)

it fails to reconnect (I cannot /whois the bot on the network). The bot will remain in this state until I ctrl+Z and kill -9 %1 it. I do this because in this state the bot does not handle SIGTERMs well: it hangs after printing

^C2020-05-23 18:59:42 INFO main main.go:83 Exiting on interrupt```

[bkero]

Stracing this process reveals:

[pid 21956] nanosleep({tv_sec=0, tv_nsec=20000}, NULL) = 0
[pid 21956] nanosleep({tv_sec=0, tv_nsec=20000}, NULL) = 0
[pid 21956] nanosleep({tv_sec=0, tv_nsec=20000}, NULL) = 0
[pid 21956] futex(0xd95850, FUTEX_WAIT_PRIVATE, 0, {tv_sec=60, tv_nsec=0}

[mich181189]

Edit: I'm not sure it was stuck here - I suspect someone restarted it before I got to it!

---

I have hit what I suspect to be this problem a few times. I attached a debugger to try to get some information. Nothing super helpful but I include it here in case it's useful to anyone

`(dlv) gr
Thread 754505 at /usr/lib/go-1.14/src/runtime/sys_linux_amd64.s:568

(dlv) bt
0 0x00000000004674b3 in runtime.futex
at /usr/lib/go-1.14/src/runtime/sys_linux_amd64.s:568
1 0x0000000000431b66 in runtime.futexsleep
at /usr/lib/go-1.14/src/runtime/os_linux.go:45
2 0x000000000040c86f in runtime.notesleep
at /usr/lib/go-1.14/src/runtime/lock_futex.go:151
3 0x000000000043c018 in runtime.stoplockedm
at /usr/lib/go-1.14/src/runtime/proc.go:1977
4 0x000000000043dc86 in runtime.schedule
at /usr/lib/go-1.14/src/runtime/proc.go:2460
5 0x000000000043e05d in runtime.park_m
at /usr/lib/go-1.14/src/runtime/proc.go:2696
6 0x000000000046320b in runtime.mcall
at /usr/lib/go-1.14/src/runtime/asm_amd64.s:318

(dlv) grs
Goroutine 1 - User: /home/mich181189/go/pkg/mod/github.com/thoj/go-ircevent@v0.0.0-20190807115034-8e7ce4b5a1eb/irc.go:238 github.com/thoj/go-ircevent.(*Connection).Loop (0x679ec3) [chan receive 449925h55m32.219338717s]
Goroutine 2 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [force gc (idle) 449919h48m51.544364881s]
Goroutine 3 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [GC sweep wait]
Goroutine 4 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [GC scavenge wait]
Goroutine 5 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [finalizer wait 449925h55m32.252438472s]
Goroutine 11 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [GC worker (idle)]
Goroutine 12 - User: /usr/lib/go-1.14/src/runtime/netpoll.go:203 internal/poll.runtime_pollWait (0x4303c5) [IO wait]
Goroutine 13 - User: /home/mich181189/go/pkg/mod/github.com/thoj/go-ircevent@v0.0.0-20190807115034-8e7ce4b5a1eb/irc.go:166 github.com/thoj/go-ircevent.(*Connection).writeLoop (0x679154) [select]
Goroutine 14 - User: /home/mich181189/go/pkg/mod/github.com/thoj/go-ircevent@v0.0.0-20190807115034-8e7ce4b5a1eb/irc.go:202 github.com/thoj/go-ircevent.(*Connection).pingLoop (0x679616) [select]
Goroutine 18 - User: /usr/lib/go-1.14/src/runtime/sema.go:56 sync.runtime_Semacquire (0x447f42) [semacquire 449925h55m32.252890161s]
Goroutine 19 - User: /usr/lib/go-1.14/src/syscall/asm_linux_amd64.s:50 syscall.Syscall6 (0x4c924a) (thread 754508)
Goroutine 20 - User: /home/mich181189/go/pkg/mod/github.com/spf13/viper@v1.5.0/viper.go:310 github.com/spf13/viper.(*Viper).WatchConfig.func1.1 (0x846556) [select 449925h55m32.252938075s]
Goroutine 27 - User: /usr/lib/go-1.14/src/runtime/sigqueue.go:147 os/signal.signal_recv (0x44c31c) (thread 754507)
Goroutine 28 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [select 449925h55m32.253059364s]
Goroutine 29 - User: /home/mich181189/irccat/main.go:87 main.(*IRCCat).signalHandler (0x8e66a6) [chan receive 449925h55m32.253093355s]
Goroutine 33 - User: /usr/lib/go-1.14/src/runtime/proc.go:305 runtime.gopark (0x437f50) [GC worker (idle)]
Goroutine 44 - User: /usr/lib/go-1.14/src/runtime/netpoll.go:203 internal/poll.runtime_pollWait (0x4303c5) [IO wait]
Goroutine 45 - User: /usr/lib/go-1.14/src/runtime/netpoll.go:203 internal/poll.runtime_pollWait (0x4303c5) [IO wait 449920h7m31.483101114s]
[18 goroutines]
`