fatal error: concurrent map iteration and map write
DIAGNOSIS:
I0301 06:02:35.315604   25953 main.go:305] ***************************
I0301 06:02:35.315657   25953 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]
I0301 06:02:35.315695   25953 main.go:307] Version release-20200219.0-72-gce4d1e45bb88
I0301 06:02:35.315715   25953 main.go:308] PID: 25953
I0301 06:02:35.315741   25953 main.go:309] UID: 0, GID: 0
I0301 06:02:35.315769   25953 main.go:310] Configuration:
I0301 06:02:35.315804   25953 main.go:311] 		RootDir: /syzkaller/managers/main/workdir/gvisor_root
I0301 06:02:35.315837   25953 main.go:312] 		Platform: ptrace
I0301 06:02:35.315857   25953 main.go:313] 		FileAccess: shared, overlay: false
I0301 06:02:35.315901   25953 main.go:314] 		Network: none, logging: false
I0301 06:02:35.315924   25953 main.go:315] 		Strace: false, max size: 1024, syscalls: []
I0301 06:02:35.315946   25953 main.go:316] ***************************
D0301 06:02:35.315994   25953 container.go:159] Load container "/syzkaller/managers/main/workdir/gvisor_root" "ci-gvisor-main-1"
D0301 06:02:35.317408   25953 container.go:592] Signal container "ci-gvisor-main-1": signal 0
D0301 06:02:35.317446   25953 sandbox.go:806] Signal sandbox "ci-gvisor-main-1"
D0301 06:02:35.317458   25953 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-1"
D0301 06:02:35.317626   25953 urpc.go:534] urpc: successfully marshalled 96 bytes.
I0301 06:02:35.477201   25953 debug.go:122] Found sandbox "ci-gvisor-main-1", PID: 19577
I0301 06:02:35.477272   25953 debug.go:131] Retrieving sandbox stacks
D0301 06:02:35.477303   25953 sandbox.go:924] Stacks sandbox "ci-gvisor-main-1"
D0301 06:02:35.477330   25953 sandbox.go:318] Connecting to sandbox "ci-gvisor-main-1"
W0301 06:02:35.477394   25953 error.go:48] FATAL ERROR: retrieving stacks: connecting to control server at PID 19577: connection refused
retrieving stacks: connecting to control server at PID 19577: connection refused
W0301 06:02:35.477591   25953 main.go:338] Failure to execute command, err: 1