panic: munmap(a00000, 200000)) failed: function not implemented

DIAGNOSIS:
I0817 10:21:54.539365   14895 x:0] ***************************
I0817 10:21:54.539525   14895 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 -alsologtostderr -platform=ptrace -file-access=exclusive -overlay -network=host debug -stacks ci-gvisor-kvm-direct-overlay-host-race-3]
I0817 10:21:54.539625   14895 x:0] Version release-20190722.1-98-gef045b914bc8
I0817 10:21:54.539650   14895 x:0] PID: 14895
I0817 10:21:54.539673   14895 x:0] UID: 0, GID: 0
I0817 10:21:54.539699   14895 x:0] Configuration:
I0817 10:21:54.539716   14895 x:0] 		RootDir: /syzkaller/managers/kvm-direct-overlay-host-race/workdir/gvisor_root
I0817 10:21:54.539739   14895 x:0] 		Platform: ptrace
I0817 10:21:54.539780   14895 x:0] 		FileAccess: exclusive, overlay: true
I0817 10:21:54.539840   14895 x:0] 		Network: host, logging: false
I0817 10:21:54.539885   14895 x:0] 		Strace: false, max size: 1024, syscalls: []
I0817 10:21:54.539935   14895 x:0] ***************************
D0817 10:21:54.540012   14895 x:0] Load container "/syzkaller/managers/kvm-direct-overlay-host-race/workdir/gvisor_root" "ci-gvisor-kvm-direct-overlay-host-race-3"
D0817 10:21:54.548603   14895 x:0] Signal container "ci-gvisor-kvm-direct-overlay-host-race-3": signal 0
D0817 10:21:54.548709   14895 x:0] Signal sandbox "ci-gvisor-kvm-direct-overlay-host-race-3"
D0817 10:21:54.548760   14895 x:0] Connecting to sandbox "ci-gvisor-kvm-direct-overlay-host-race-3"
D0817 10:21:54.549567   14895 x:0] urpc: successfully marshalled 120 bytes.
I0817 10:21:54.899792   14895 x:0] Found sandbox "ci-gvisor-kvm-direct-overlay-host-race-3", PID: 46510
I0817 10:21:54.899898   14895 x:0] Retrieving sandbox stacks
D0817 10:21:54.899921   14895 x:0] Stacks sandbox "ci-gvisor-kvm-direct-overlay-host-race-3"
D0817 10:21:54.899999   14895 x:0] Connecting to sandbox "ci-gvisor-kvm-direct-overlay-host-race-3"
D0817 10:21:54.900177   14895 x:0] urpc: successfully marshalled 36 bytes.
W0817 10:21:54.981582   14895 x:0] FATAL ERROR: retrieving stacks: getting sandbox "ci-gvisor-kvm-direct-overlay-host-race-3" stacks: urpc method "debug.Stacks" failed: connection reset by peer
retrieving stacks: getting sandbox "ci-gvisor-kvm-direct-overlay-host-race-3" stacks: urpc method "debug.Stacks" failed: connection reset by peer
W0817 10:21:54.981883   14895 x:0] Failure to execute command, err: 1