panic: munmap(600000, 200000)) failed: function not implemented

goroutine 634035 [running]:
DIAGNOSIS:
I0522 23:45:51.704232   16317 x:0] ***************************
I0522 23:45:51.704362   16317 x:0] Args: [/syzkaller/managers/kvm-direct-overlay-host-race/current/image -root /syzkaller/managers/kvm-direct-overlay-host-race/workdir/gvisor_root -watchdog-action=panic -network=none -debug -platform=ptrace -file-access=exclusive -overlay -network=host debug -stacks ci-gvisor-kvm-direct-overlay-host-race-1]
I0522 23:45:51.704438   16317 x:0] Version release-20190304.1-220-g711290a7f6c4
I0522 23:45:51.704455   16317 x:0] PID: 16317
I0522 23:45:51.704477   16317 x:0] UID: 0, GID: 0
I0522 23:45:51.704517   16317 x:0] Configuration:
I0522 23:45:51.704534   16317 x:0] 		RootDir: /syzkaller/managers/kvm-direct-overlay-host-race/workdir/gvisor_root
I0522 23:45:51.704573   16317 x:0] 		Platform: ptrace
I0522 23:45:51.704600   16317 x:0] 		FileAccess: exclusive, overlay: true
I0522 23:45:51.704637   16317 x:0] 		Network: host, logging: false
I0522 23:45:51.704665   16317 x:0] 		Strace: false, max size: 1024, syscalls: []
I0522 23:45:51.704704   16317 x:0] ***************************
D0522 23:45:51.704772   16317 x:0] Load container "/syzkaller/managers/kvm-direct-overlay-host-race/workdir/gvisor_root" "ci-gvisor-kvm-direct-overlay-host-race-1"
D0522 23:45:51.711503   16317 x:0] Signal container "ci-gvisor-kvm-direct-overlay-host-race-1": signal 0
D0522 23:45:51.711587   16317 x:0] Signal sandbox "ci-gvisor-kvm-direct-overlay-host-race-1"
D0522 23:45:51.711643   16317 x:0] Connecting to sandbox "ci-gvisor-kvm-direct-overlay-host-race-1"
D0522 23:45:51.712444   16317 x:0] urpc: successfully marshalled 120 bytes.
I0522 23:45:51.998236   16317 x:0] Found sandbox "ci-gvisor-kvm-direct-overlay-host-race-1", PID: 62283
I0522 23:45:51.998290   16317 x:0] Retrieving sandbox stacks
D0522 23:45:51.998313   16317 x:0] Stacks sandbox "ci-gvisor-kvm-direct-overlay-host-race-1"
D0522 23:45:51.998349   16317 x:0] Connecting to sandbox "ci-gvisor-kvm-direct-overlay-host-race-1"
D0522 23:45:51.998468   16317 x:0] urpc: successfully marshalled 36 bytes.
W0522 23:45:52.058435   16317 x:0] FATAL ERROR: retrieving stacks: getting sandbox "ci-gvisor-kvm-direct-overlay-host-race-1" stacks: urpc method "debug.Stacks" failed: connection reset by peer
retrieving stacks: getting sandbox "ci-gvisor-kvm-direct-overlay-host-race-1" stacks: urpc method "debug.Stacks" failed: connection reset by peer