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

DIAGNOSIS:
I1003 00:16:27.106197   25145 x:0] ***************************
I1003 00:16:27.106281   25145 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 -alsologtostderr -platform=ptrace -file-access=shared -network=host debug -stacks ci-gvisor-ptrace-direct-overlay-host-3]
I1003 00:16:27.106298   25145 x:0] Version release-20190806.1-228-g2016cc283cbd
I1003 00:16:27.106305   25145 x:0] PID: 25145
I1003 00:16:27.106312   25145 x:0] UID: 0, GID: 0
I1003 00:16:27.106316   25145 x:0] Configuration:
I1003 00:16:27.106320   25145 x:0] 		RootDir: /syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root
I1003 00:16:27.106328   25145 x:0] 		Platform: ptrace
I1003 00:16:27.106332   25145 x:0] 		FileAccess: shared, overlay: false
I1003 00:16:27.106342   25145 x:0] 		Network: host, logging: false
I1003 00:16:27.106350   25145 x:0] 		Strace: false, max size: 1024, syscalls: []
I1003 00:16:27.106356   25145 x:0] ***************************
D1003 00:16:27.106412   25145 x:0] Load container "/syzkaller/managers/ptrace-direct-overlay-host/workdir/gvisor_root" "ci-gvisor-ptrace-direct-overlay-host-3"
D1003 00:16:27.108124   25145 x:0] Signal container "ci-gvisor-ptrace-direct-overlay-host-3": signal 0
D1003 00:16:27.108155   25145 x:0] Signal sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D1003 00:16:27.108165   25145 x:0] Connecting to sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D1003 00:16:27.108572   25145 x:0] urpc: successfully marshalled 118 bytes.
I1003 00:16:27.554541   25145 x:0] Found sandbox "ci-gvisor-ptrace-direct-overlay-host-3", PID: 3641
I1003 00:16:27.554569   25145 x:0] Retrieving sandbox stacks
D1003 00:16:27.554575   25145 x:0] Stacks sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D1003 00:16:27.554582   25145 x:0] Connecting to sandbox "ci-gvisor-ptrace-direct-overlay-host-3"
D1003 00:16:27.554651   25145 x:0] urpc: successfully marshalled 36 bytes.
W1003 00:16:27.621319   25145 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
W1003 00:16:27.621407   25145 x:0] Failure to execute command, err: 1