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

goroutine 976202 [running]:
DIAGNOSIS:
I0304 08:04:40.873307   21073 main.go:305] ***************************
I0304 08:04:40.873383   21073 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 08:04:40.873439   21073 main.go:307] Version release-20200219.0-72-gce4d1e45bb88
I0304 08:04:40.873473   21073 main.go:308] PID: 21073
I0304 08:04:40.873504   21073 main.go:309] UID: 0, GID: 0
I0304 08:04:40.873531   21073 main.go:310] Configuration:
I0304 08:04:40.873557   21073 main.go:311] 		RootDir: /syzkaller/managers/main/workdir/gvisor_root
I0304 08:04:40.873594   21073 main.go:312] 		Platform: ptrace
I0304 08:04:40.873621   21073 main.go:313] 		FileAccess: shared, overlay: false
I0304 08:04:40.873655   21073 main.go:314] 		Network: none, logging: false
I0304 08:04:40.873684   21073 main.go:315] 		Strace: false, max size: 1024, syscalls: []
I0304 08:04:40.873712   21073 main.go:316] ***************************
D0304 08:04:40.874104   21073 container.go:159] Load container "/syzkaller/managers/main/workdir/gvisor_root" "ci-gvisor-main-0"
D0304 08:04:40.876257   21073 container.go:592] Signal container "ci-gvisor-main-0": signal 0
D0304 08:04:40.876364   21073 sandbox.go:806] Signal sandbox "ci-gvisor-main-0"
D0304 08:04:40.876435   21073 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-0"
D0304 08:04:40.876778   21073 urpc.go:534] urpc: successfully marshalled 96 bytes.
I0304 08:04:41.507186   21073 debug.go:122] Found sandbox "ci-gvisor-main-0", PID: 64289
I0304 08:04:41.507243   21073 debug.go:131] Retrieving sandbox stacks
D0304 08:04:41.507266   21073 sandbox.go:924] Stacks sandbox "ci-gvisor-main-0"
D0304 08:04:41.507278   21073 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-0"
W0304 08:04:41.507319   21073 error.go:48] FATAL ERROR: retrieving stacks: connecting to control server at PID 64289: connection refused
retrieving stacks: connecting to control server at PID 64289: connection refused
W0304 08:04:41.507478   21073 main.go:338] Failure to execute command, err: 1