panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x579cd0]

goroutine 258091 [running]:
panic({0xcc4e20, 0x1c0ee20})
	GOROOT/src/runtime/panic.go:987 +0x3ac fp=0x40060f5020 sp=0x40060f4f60 pc=0x450ac
runtime.panicmem()
	GOROOT/src/runtime/panic.go:260 +0x48 fp=0x40060f5040 sp=0x40060f5020 pc=0x43a28
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x214 fp=0x40060f5080 sp=0x40060f5040 pc=0x5c7f4
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x40077e8768, 0x40060a0cb5?)
	pkg/sentry/kernel/tty.go:54 +0x80 fp=0x40060f5120 sp=0x40060f5090 pc=0x579cd0
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x40060f53b8, 0x40060c2000, 0x40060c2010, {0x40060a0c80?, 0x4007800000?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:409 +0x338 fp=0x40060f5350 sp=0x40060f5120 pc=0x8b4648
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0x40060c2010, 0x4002ca2000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xe8 fp=0x40060f53c0 sp=0x40060f5350 pc=0x8b7068
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0x40060c2010, {0x10e5318, 0x4007800000}, {{0x10dfbc8, 0x4002ca2000}, {0x0, 0x1, 0x200001c0, 0x7e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x180 fp=0x40060f5470 sp=0x40060f53c0 pc=0x8b6950
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0x40060c2000, {0x10e5318, 0x4007800000}, {{0x10dfbc8, 0x4002ca2000}, {0x0, 0x1, 0x200001c0, 0x7e}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xb0 fp=0x40060f5500 sp=0x40060f5470 pc=0x8b3690
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x40060f5588?, {0x10e5318?, 0x4007800000?}, {{0x10dfbc8, 0x4002ca2000}, {0x0, 0x1, 0x200001c0, 0x7e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x78 fp=0x40060f5560 sp=0x40060f5500 pc=0x8b53b8
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0x40051b4200, {0x10e5318, 0x4007800000}, {{0x10dfbc8, 0x4002ca2000}, {0x0, 0x1, 0x200001c0, 0x7e}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x9c fp=0x40060f55e0 sp=0x40060f5560 pc=0x34c56c
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x40070c5d40?, 0x40051b4200, {{0x10dfbc8, 0x4002ca2000}, {0x0, 0x1, 0x200001c0, 0x7e}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x94 fp=0x40060f57b0 sp=0x40060f55e0 pc=0x6c0394
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0x4007800000, {{0x3}, {0x200001c0}, {0x7e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x180 fp=0x40060f58f0 sp=0x40060f57b0 pc=0x6bfc60
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0x4007800000, 0x40, {{0x3}, {0x200001c0}, {0x7e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x678 fp=0x40060f5c30 sp=0x40060f58f0 pc=0x570318
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0x4007800000, 0x0?, {{0x3}, {0x200001c0}, {0x7e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x48 fp=0x40060f5c90 sp=0x40060f5c30 pc=0x5715f8
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0x40060f5d48?, 0x52e478?, {{0x3}, {0x200001c0}, {0x7e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x7c fp=0x40060f5cf0 sp=0x40060f5c90 pc=0x5711fc
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0x4009683c70?)
	pkg/sentry/kernel/task_syscall.go:257 +0x330 fp=0x40060f5df0 sp=0x40060f5cf0 pc=0x570f20
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x40051b4180?, 0x4007800000)
	pkg/sentry/kernel/task_run.go:265 +0x1170 fp=0x40060f5f40 sp=0x40060f5df0 pc=0x564200
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0x4007800000, 0x10f0)
	pkg/sentry/kernel/task_run.go:94 +0x208 fp=0x40060f5fb0 sp=0x40060f5f40 pc=0x562a58
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2c fp=0x40060f5fd0 sp=0x40060f5fb0 pc=0x56ea4c
runtime.goexit()
	src/runtime/asm_arm64.s:1172 +0x4 fp=0x40060f5fd0 sp=0x40060f5fd0 pc=0x7a444
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xf8