panic: ptrace status unexpected: got 31, wanted stopped

DIAGNOSIS:
I0602 02:24:41.160077   35749 x:0] ***************************
I0602 02:24:41.160126   35749 x:0] Args: [/syzkaller/managers/ptrace-direct-overlay-host/current/image -root /syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root -watchdog-action=panic -network=none -debug -platform=ptrace -file-access=shared -network=host debug -stacks ci-gvisor-ptrace-direct-overlay-host-3]
I0602 02:24:41.160138   35749 x:0] Version release-20190529.1-40-g3577a4f6910f
I0602 02:24:41.160143   35749 x:0] PID: 35749
I0602 02:24:41.160149   35749 x:0] UID: 0, GID: 0
I0602 02:24:41.160152   35749 x:0] Configuration:
I0602 02:24:41.160163   35749 x:0] 		RootDir: /syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root
I0602 02:24:41.160179   35749 x:0] 		Platform: ptrace
I0602 02:24:41.160184   35749 x:0] 		FileAccess: shared, overlay: false
I0602 02:24:41.160190   35749 x:0] 		Network: host, logging: false
I0602 02:24:41.160196   35749 x:0] 		Strace: false, max size: 1024, syscalls: []
I0602 02:24:41.160199   35749 x:0] ***************************
D0602 02:24:41.160217   35749 x:0] Load container "/syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root" "ci-gvisor-ptrace-direct-overlay-host-3"
D0602 02:24:41.161806   35749 x:0] Signal container "ci-gvisor-ptrace-direct-overlay-host-3": signal 0
D0602 02:24:41.161844   35749 x:0] Signal sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D0602 02:24:41.161850   35749 x:0] Connecting to sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D0602 02:24:41.162000   35749 x:0] urpc: successfully marshalled 118 bytes.
I0602 02:24:41.567360   35749 x:0] Found sandbox "ci-gvisor-ptrace-direct-overlay-host-3", PID: 7705
I0602 02:24:41.567375   35749 x:0] Retrieving sandbox stacks
D0602 02:24:41.567379   35749 x:0] Stacks sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D0602 02:24:41.567384   35749 x:0] Connecting to sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D0602 02:24:41.567457   35749 x:0] urpc: successfully marshalled 36 bytes.
W0602 02:24:41.658395   35749 x:0] FATAL ERROR: retrieving stacks: getting sandbox "ci-gvisor-ptrace-direct-overlay-host-3" stacks: urpc method "debug.Stacks" failed: connection reset by peer
retrieving stacks: getting sandbox "ci-gvisor-ptrace-direct-overlay-host-3" stacks: urpc method "debug.Stacks" failed: connection reset by peer