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

goroutine 653962 [running]:
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*subprocess).Unmap(0xc42060a360, 0xa00000, 0x200000)
	pkg/sentry/platform/ptrace/subprocess.go:556 +0x51f
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).unmapASLocked(0xc42317f900, 0xa00000, 0xc00000)
	pkg/sentry/mm/address_space.go:217 +0xf9
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).breakCopyOnWriteLocked(0xc42317f900, 0xc42317ff68, 0x7, 0xa29000, 0xa2a000, 0xa29000, 0xa2a000, 0xc42317ff68, 0x7, 0xc42317ff68)
	pkg/sentry/mm/pma.go:449 +0xd25
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).getPMAsLocked(0xc42317f900, 0x10ec340, 0xc423762000, 0xc42317f970, 0x5, 0xa29000, 0xa2a000, 0x1, 0xc42317f970, 0x6, ...)
	pkg/sentry/mm/pma.go:142 +0x358
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).HandleUserFault(0xc42317f900, 0x10ec340, 0xc423762000, 0xa29c78, 0xc423000101, 0x7f6879ae2a30, 0xc422f780c0, 0x101)
	pkg/sentry/mm/syscalls.go:55 +0x1a5
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc423762000, 0x10dd380, 0x0)
	pkg/sentry/kernel/task_run.go:235 +0xc1b
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).run(0xc423762000, 0x6071)
	pkg/sentry/kernel/task_run.go:95 +0x265
created by gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:251 +0x194