panic: runtime error: index out of range [1] with length 0

goroutine 1808804 [running]:
DIAGNOSIS:
I0304 03:30:20.952053    6124 main.go:305] ***************************
I0304 03:30:20.952118    6124 main.go:306] Args: [/syzkaller/managers/main/current/image -root /syzkaller/managers/main/workdir/gvisor_root -watchdog-action=panic -network=none -debug -alsologtostderr -platform=ptrace -file-access=shared -network=none debug -stacks --ps ci-gvisor-main-1]
I0304 03:30:20.952163    6124 main.go:307] Version release-20200219.0-72-gce4d1e45bb88
I0304 03:30:20.952194    6124 main.go:308] PID: 6124
I0304 03:30:20.952221    6124 main.go:309] UID: 0, GID: 0
I0304 03:30:20.952248    6124 main.go:310] Configuration:
I0304 03:30:20.952275    6124 main.go:311] 		RootDir: /syzkaller/managers/main/workdir/gvisor_root
I0304 03:30:20.952318    6124 main.go:312] 		Platform: ptrace
I0304 03:30:20.952345    6124 main.go:313] 		FileAccess: shared, overlay: false
I0304 03:30:20.952381    6124 main.go:314] 		Network: none, logging: false
I0304 03:30:20.952418    6124 main.go:315] 		Strace: false, max size: 1024, syscalls: []
I0304 03:30:20.952452    6124 main.go:316] ***************************
D0304 03:30:20.952526    6124 container.go:159] Load container "/syzkaller/managers/main/workdir/gvisor_root" "ci-gvisor-main-1"
D0304 03:30:20.954068    6124 container.go:592] Signal container "ci-gvisor-main-1": signal 0
D0304 03:30:20.954112    6124 sandbox.go:806] Signal sandbox "ci-gvisor-main-1"
D0304 03:30:20.954127    6124 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-1"
D0304 03:30:20.954287    6124 urpc.go:534] urpc: successfully marshalled 96 bytes.
I0304 03:30:22.013132    6124 debug.go:122] Found sandbox "ci-gvisor-main-1", PID: 25119
I0304 03:30:22.013171    6124 debug.go:131] Retrieving sandbox stacks
D0304 03:30:22.013193    6124 sandbox.go:924] Stacks sandbox "ci-gvisor-main-1"
D0304 03:30:22.013207    6124 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-1"
W0304 03:30:22.013249    6124 error.go:48] FATAL ERROR: retrieving stacks: connecting to control server at PID 25119: connection refused
retrieving stacks: connecting to control server at PID 25119: connection refused
W0304 03:30:22.013398    6124 main.go:338] Failure to execute command, err: 1