panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x4f5264]

goroutine 345592 [running]:
panic({0xbc4dc0, 0x1939a60})
	GOROOT/src/runtime/panic.go:987 +0x3ac fp=0x400743ef50 sp=0x400743ee90 pc=0x4526c
runtime.panicmem()
	GOROOT/src/runtime/panic.go:260 +0x48 fp=0x400743ef70 sp=0x400743ef50 pc=0x43be8
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x214 fp=0x400743efb0 sp=0x400743ef70 pc=0x5c9b4
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x199e1b0?, 0x4006330012?)
	pkg/sentry/kernel/tty.go:54 +0xc4 fp=0x400743f050 sp=0x400743efc0 pc=0x4f5264
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0xb0, 0x400632a000, 0x400632a010, {0x4006330000?, 0x4002533890?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x2bc fp=0x400743f280 sp=0x400743f050 pc=0x7d773c
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0x400632a010, 0xfbb6f8?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xb4 fp=0x400743f2f0 sp=0x400743f280 pc=0x7d9cc4
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0x400632a010, {0xfbb6f8, 0x40070e7500}, {{0xfb5d28, 0x4006f10000}, {0x0, 0x1, 0x20002980, 0xb0}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1d8 fp=0x400743f3d0 sp=0x400743f2f0 pc=0x7d9658
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0x400632a000, {0xfbb6f8?, 0x40070e7500?}, {{0xfb5d28, 0x4006f10000}, {0x0, 0x1, 0x20002980, 0xb0}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xd4 fp=0x400743f460 sp=0x400743f3d0 pc=0x7d69c4
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x400743f401?, {0xfbb6f8?, 0x40070e7500?}, {{0xfb5d28, 0x4006f10000}, {0x0, 0x1, 0x20002980, 0xb0}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x64 fp=0x400743f4c0 sp=0x400743f460 pc=0x7d81d4
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0x4009226b80, {0xfbb6f8, 0x40070e7500}, {{0xfb5d28, 0x4006f10000}, {0x0, 0x1, 0x20002980, 0xb0}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x80 fp=0x400743f540 sp=0x400743f4c0 pc=0x3183d0
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x0?, 0x4009226b80, {{0xfb5d28, 0x4006f10000}, {0x0, 0x1, 0x20002980, 0xb0}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x88 fp=0x400743f700 sp=0x400743f540 pc=0x60e578
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0x40070e7500, {{0x5}, {0x20002980}, {0xb0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x134 fp=0x400743f840 sp=0x400743f700 pc=0x60df34
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0x40070e7500, 0x40, {{0x5}, {0x20002980}, {0xb0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x5a0 fp=0x400743fc30 sp=0x400743f840 pc=0x4ed030
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0x40070e7500, 0x0?, {{0x5}, {0x20002980}, {0xb0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x3c fp=0x400743fc90 sp=0x400743fc30 pc=0x4edf2c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0x400492b5e8?, 0x1c62c?, {{0x5}, {0x20002980}, {0xb0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x58 fp=0x400743fcf0 sp=0x400743fc90 pc=0x4edc48
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0x4007f3bba0?)
	pkg/sentry/kernel/task_syscall.go:257 +0x284 fp=0x400743fdf0 sp=0x400743fcf0 pc=0x4ed9f4
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x4001fd9280?, 0x40070e7500)
	pkg/sentry/kernel/task_run.go:265 +0xdbc fp=0x400743ff40 sp=0x400743fdf0 pc=0x4e31dc
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0x40070e7500, 0x4955)
	pkg/sentry/kernel/task_run.go:94 +0x190 fp=0x400743ffb0 sp=0x400743ff40 pc=0x4e1e40
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2c fp=0x400743ffd0 sp=0x400743ffb0 pc=0x4ebaec
runtime.goexit()
	src/runtime/asm_arm64.s:1172 +0x4 fp=0x400743ffd0 sp=0x400743ffd0 pc=0x7a604
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xe4