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

goroutine 3141366 [running]:
DIAGNOSIS:
I0304 09:20:38.567427    6041 main.go:305] ***************************
I0304 09:20:38.567487    6041 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-0]
I0304 09:20:38.567527    6041 main.go:307] Version release-20200219.0-72-gce4d1e45bb88
I0304 09:20:38.567551    6041 main.go:308] PID: 6041
I0304 09:20:38.567584    6041 main.go:309] UID: 0, GID: 0
I0304 09:20:38.567610    6041 main.go:310] Configuration:
I0304 09:20:38.567633    6041 main.go:311] 		RootDir: /syzkaller/managers/main/workdir/gvisor_root
I0304 09:20:38.567663    6041 main.go:312] 		Platform: ptrace
I0304 09:20:38.567697    6041 main.go:313] 		FileAccess: shared, overlay: false
I0304 09:20:38.567726    6041 main.go:314] 		Network: none, logging: false
I0304 09:20:38.567755    6041 main.go:315] 		Strace: false, max size: 1024, syscalls: []
I0304 09:20:38.567779    6041 main.go:316] ***************************
D0304 09:20:38.567973    6041 container.go:159] Load container "/syzkaller/managers/main/workdir/gvisor_root" "ci-gvisor-main-0"
D0304 09:20:38.569922    6041 container.go:592] Signal container "ci-gvisor-main-0": signal 0
D0304 09:20:38.569963    6041 sandbox.go:806] Signal sandbox "ci-gvisor-main-0"
D0304 09:20:38.570032    6041 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-0"
D0304 09:20:38.570210    6041 urpc.go:534] urpc: successfully marshalled 96 bytes.
I0304 09:20:39.862229    6041 debug.go:122] Found sandbox "ci-gvisor-main-0", PID: 8228
I0304 09:20:39.862289    6041 debug.go:131] Retrieving sandbox stacks
D0304 09:20:39.862334    6041 sandbox.go:924] Stacks sandbox "ci-gvisor-main-0"
D0304 09:20:39.862355    6041 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-0"
W0304 09:20:39.862402    6041 error.go:48] FATAL ERROR: retrieving stacks: connecting to control server at PID 8228: connection refused
retrieving stacks: connecting to control server at PID 8228: connection refused
W0304 09:20:39.862523    6041 main.go:338] Failure to execute command, err: 1