panic: ptrace status unexpected: got 9, wanted stopped

goroutine 3523960 [running]:
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*thread).wait(0xc0014881e0, 0x0, 0x401b)
	pkg/sentry/platform/ptrace/subprocess.go:323 +0x521
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*thread).attach(0xc0014881e0)
	pkg/sentry/platform/ptrace/subprocess.go:265 +0xaf
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*subprocess).newThread(0xc0023744c0, 0xc0016e2000)
	pkg/sentry/platform/ptrace/subprocess.go:249 +0xb6
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*subprocess).newThread-fm(0xc001e1f970)
	pkg/sentry/platform/ptrace/subprocess.go:462 +0x42
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*threadPool).lookupOrCreate(0xc0023744d8, 0x4437, 0xc001e1fa28, 0x827c03)
	pkg/sentry/platform/ptrace/subprocess.go:96 +0x2d3
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*subprocess).syscall(0xc0023744c0, 0x9, 0xc001e1fa90, 0x6, 0x6, 0x0, 0x0, 0x0)
	pkg/sentry/platform/ptrace/subprocess.go:560 +0xaf
gvisor.googlesource.com/gvisor/pkg/sentry/platform/ptrace.(*subprocess).MapFile(0xc0023744c0, 0x20000000, 0xc, 0x49600000, 0x49800000, 0x10101, 0x7, 0x45d2c2)
	pkg/sentry/platform/ptrace/subprocess.go:571 +0x126
gvisor.googlesource.com/gvisor/pkg/sentry/platform/filemem.(*FileMem).MapInto(0xc000151b00, 0x11fbea0, 0xc0023744c0, 0x20000000, 0x49600000, 0x49800000, 0x10101, 0xc000672d80, 0xc001aca650)
	pkg/sentry/platform/filemem/filemem.go:512 +0x11d
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).mapASLocked(0xc001aca000, 0xc001aca668, 0x7, 0x2001d000, 0x2001e000, 0x2001d000, 0x2001e000, 0x0)
	pkg/sentry/mm/address_space.go:184 +0x38b
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).HandleUserFault(0xc001aca000, 0x11fc860, 0xc000e50a80, 0x2001d000, 0x1, 0x7fc5a5db98a0, 0x0, 0x1)
	pkg/sentry/mm/syscalls.go:70 +0x295
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc000e50a80, 0x11edd80, 0x0)
	pkg/sentry/kernel/task_run.go:251 +0x987
gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).run(0xc000e50a80, 0x7d48)
	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