panic: ptrace status unexpected: got 31, wanted stopped

DIAGNOSIS:
I0416 15:58:04.924432   65047 x:0] ***************************
I0416 15:58:04.924492   65047 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-2]
I0416 15:58:04.924520   65047 x:0] Version release-20190304.1-116-g546a1df7d15f
I0416 15:58:04.924525   65047 x:0] PID: 65047
I0416 15:58:04.924530   65047 x:0] UID: 0, GID: 0
I0416 15:58:04.924533   65047 x:0] Configuration:
I0416 15:58:04.924547   65047 x:0] 		RootDir: /syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root
I0416 15:58:04.924550   65047 x:0] 		Platform: ptrace
I0416 15:58:04.924563   65047 x:0] 		FileAccess: shared, overlay: false
I0416 15:58:04.924568   65047 x:0] 		Network: host, logging: false
I0416 15:58:04.924574   65047 x:0] 		Strace: false, max size: 1024, syscalls: []
I0416 15:58:04.924578   65047 x:0] ***************************
D0416 15:58:04.925385   65047 x:0] Load container "/syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root" "ci-gvisor-ptrace-direct-overlay-host-2"
D0416 15:58:04.927189   65047 x:0] Signal container "ci-gvisor-ptrace-direct-overlay-host-2": signal 0
D0416 15:58:04.927215   65047 x:0] Signal sandbox "ci-gvisor-ptrace-direct-overlay-host-2"
D0416 15:58:04.927221   65047 x:0] Connecting to sandbox "ci-gvisor-ptrace-direct-overlay-host-2"
D0416 15:58:04.932838   65047 x:0] urpc: successfully marshalled 118 bytes.
I0416 15:58:05.340296   65047 x:0] Found sandbox "ci-gvisor-ptrace-direct-overlay-host-2", PID: 60841
I0416 15:58:05.340322   65047 x:0] Retrieving sandbox stacks
D0416 15:58:05.340327   65047 x:0] Stacks sandbox "ci-gvisor-ptrace-direct-overlay-host-2"
D0416 15:58:05.340345   65047 x:0] Connecting to sandbox "ci-gvisor-ptrace-direct-overlay-host-2"
D0416 15:58:05.340469   65047 x:0] urpc: successfully marshalled 36 bytes.
W0416 15:58:05.426770   65047 x:0] FATAL ERROR: retrieving stacks: getting sandbox "ci-gvisor-ptrace-direct-overlay-host-2" stacks: urpc method "debug.Stacks" failed: connection reset by peer
retrieving stacks: getting sandbox "ci-gvisor-ptrace-direct-overlay-host-2" stacks: urpc method "debug.Stacks" failed: connection reset by peer