panic: munmap(7fb707000000, 200000)) failed: function not implemented

goroutine 192 [running]:
DIAGNOSIS:


Error collecting stacks: failed to run ["/syzkaller/managers/ptrace-proxy-sandbox-race/current/image" "-root" "/syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root" "-watchdog-action=panic" "-network=none" "-debug" "-platform=ptrace" "-file-access=shared" "-network=sandbox" "debug" "-stacks" "ci-gvisor-ptrace-proxy-sandbox-race-0"]: exit status 128
I0301 14:35:00.200463   44251 x:0] ***************************
I0301 14:35:00.200779   44251 x:0] Args: [/syzkaller/managers/ptrace-proxy-sandbox-race/current/image -root /syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root -watchdog-action=panic -network=none -debug -platform=ptrace -file-access=shared -network=sandbox debug -stacks ci-gvisor-ptrace-proxy-sandbox-race-0]
I0301 14:35:00.200946   44251 x:0] Git Revision: 383078688353feb4ae3714aa4b1d79aea519f7a4
I0301 14:35:00.201043   44251 x:0] PID: 44251
I0301 14:35:00.201117   44251 x:0] UID: 0, GID: 0
I0301 14:35:00.201183   44251 x:0] Configuration:
I0301 14:35:00.201238   44251 x:0] 		RootDir: /syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root
I0301 14:35:00.201282   44251 x:0] 		Platform: ptrace
I0301 14:35:00.201360   44251 x:0] 		FileAccess: shared, overlay: false
I0301 14:35:00.201387   44251 x:0] 		Network: sandbox, logging: false
I0301 14:35:00.201435   44251 x:0] 		Strace: false, max size: 1024, syscalls: []
I0301 14:35:00.201461   44251 x:0] ***************************
D0301 14:35:00.201611   44251 x:0] Load container "/syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root" "ci-gvisor-ptrace-proxy-sandbox-race-0"
D0301 14:35:00.207624   44251 x:0] Signal container "ci-gvisor-ptrace-proxy-sandbox-race-0": signal 0
D0301 14:35:00.207944   44251 x:0] Signal sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0"
D0301 14:35:00.207987   44251 x:0] Connecting to sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0"
D0301 14:35:00.209860   44251 x:0] urpc: successfully marshalled 117 bytes.
I0301 14:35:00.711047   44251 x:0] Found sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0", PID: 52860
I0301 14:35:00.711166   44251 x:0] Retrieving sandbox stacks
D0301 14:35:00.711198   44251 x:0] Stacks sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0"
D0301 14:35:00.711340   44251 x:0] Connecting to sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0"
D0301 14:35:00.711547   44251 x:0] urpc: successfully marshalled 36 bytes.
W0301 14:35:00.817573   44251 x:0] FATAL ERROR: retrieving stacks: getting sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0" stacks: urpc method "debug.Stacks" failed: connection reset by peer
retrieving stacks: getting sandbox "ci-gvisor-ptrace-proxy-sandbox-race-0" stacks: urpc method "debug.Stacks" failed: connection reset by peer
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*subprocess).Unmap(0xc000148200, 0x7fb707000000, 0x200000)
	pkg/sentry/platform/ptrace/subprocess.go:608 +0x455
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).unmapASLocked(0xc000273b00, 0x7fb707000000, 0x7fb707200000)
	pkg/sentry/mm/address_space.go:215 +0xf5
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).breakCopyOnWriteLocked(0xc000273b00, 0xc0002741f0, 0x7, 0x7fb7071fe000, 0x7fb7071ff000, 0x7fb7071fe000, 0x7fb7071ff000, 0xc0002741f0, 0x7, 0xc0002741f0)
	pkg/sentry/mm/pma.go:457 +0xd51
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).getPMAsLocked(0xc000273b00, 0x1248ba0, 0xc0003f2000, 0xc000273b70, 0xa, 0x7fb7071fe000, 0x7fb7071ff000, 0x1, 0xc000273b70, 0xb, ...)
	pkg/sentry/mm/pma.go:146 +0x39b
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).HandleUserFault(0xc000273b00, 0x1248ba0, 0xc0003f2000, 0x7fb7071fead8, 0x101, 0x7fb7071feae0, 0x0, 0x101)
	pkg/sentry/mm/syscalls.go:57 +0x1ae
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc0003f2000, 0x123a3c0, 0x0)
	pkg/sentry/kernel/task_run.go:251 +0x987
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).run(0xc0003f2000, 0x61)
	pkg/sentry/kernel/task_run.go:91 +0x24c
created by gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:279 +0x19e