fatal error: thread exhaustion
DIAGNOSIS:
I0429 09:27:50.356627   47611 x:0] ***************************
I0429 09:27:50.356684   47611 x:0] Args: [/syzkaller/managers/kvm-direct-sandbox/current/image -root /syzkaller/managers/kvm-direct-sandbox/workdir/gvisor_root -watchdog-action=panic -network=none -debug -platform=kvm -file-access=exclusive -network=sandbox debug -stacks ci-gvisor-kvm-direct-sandbox-0]
I0429 09:27:50.356697   47611 x:0] Version release-20190304.1-153-g43dff57b878e
I0429 09:27:50.356702   47611 x:0] PID: 47611
I0429 09:27:50.356709   47611 x:0] UID: 0, GID: 0
I0429 09:27:50.356712   47611 x:0] Configuration:
I0429 09:27:50.356716   47611 x:0] 		RootDir: /syzkaller/managers/kvm-direct-sandbox/workdir/gvisor_root
I0429 09:27:50.356720   47611 x:0] 		Platform: kvm
I0429 09:27:50.356733   47611 x:0] 		FileAccess: exclusive, overlay: false
I0429 09:27:50.356744   47611 x:0] 		Network: sandbox, logging: false
I0429 09:27:50.356750   47611 x:0] 		Strace: false, max size: 1024, syscalls: []
I0429 09:27:50.356754   47611 x:0] ***************************
D0429 09:27:50.356773   47611 x:0] Load container "/syzkaller/managers/kvm-direct-sandbox/workdir/gvisor_root" "ci-gvisor-kvm-direct-sandbox-0"
D0429 09:27:50.358469   47611 x:0] Signal container "ci-gvisor-kvm-direct-sandbox-0": signal 0
D0429 09:27:50.358496   47611 x:0] Signal sandbox "ci-gvisor-kvm-direct-sandbox-0"
D0429 09:27:50.358501   47611 x:0] Connecting to sandbox "ci-gvisor-kvm-direct-sandbox-0"
D0429 09:27:50.358630   47611 x:0] urpc: successfully marshalled 110 bytes.
I0429 09:28:08.221374   47611 x:0] Found sandbox "ci-gvisor-kvm-direct-sandbox-0", PID: 63813
I0429 09:28:08.221398   47611 x:0] Retrieving sandbox stacks
D0429 09:28:08.221404   47611 x:0] Stacks sandbox "ci-gvisor-kvm-direct-sandbox-0"
D0429 09:28:08.221409   47611 x:0] Connecting to sandbox "ci-gvisor-kvm-direct-sandbox-0"
W0429 09:28:08.221441   47611 x:0] FATAL ERROR: retrieving stacks: connecting to control server at PID 63813: connection refused
retrieving stacks: connecting to control server at PID 63813: connection refused