panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x9d6041]

goroutine 701271 [running]:
panic({0x11ee280, 0x210cda0})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0059eb078 sp=0xc0059eafb8 pc=0x436a3b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0059eb0d8 sp=0xc0059eb078 pc=0x44e05d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0xc007900510, 0xc009833114?)
	pkg/sentry/kernel/tty.go:54 +0xa1 fp=0xc0059eb168 sp=0xc0059eb0d8 pc=0x9d6041
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x6bdc5a, 0xc007974000, 0xc007974010, {0xc009833110?, 0xc00a5b0a80?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:409 +0x3c6 fp=0xc0059eb398 sp=0xc0059eb168 pc=0xd6e366
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc007974010, 0xc00a5b0a80?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xce fp=0xc0059eb400 sp=0xc0059eb398 pc=0xd7130e
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc007974010, {0x15f5f58, 0xc00a5b0a80}, {{0x15f0490, 0xc006204000}, {0x0, 0x1, 0x20000180, 0x2f}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1f9 fp=0xc0059eb4b0 sp=0xc0059eb400 pc=0xd70bd9
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc007974000, {0x15f5f58, 0xc00a5b0a80}, {{0x15f0490, 0xc006204000}, {0x0, 0x1, 0x20000180, 0x2f}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xcd fp=0xc0059eb540 sp=0xc0059eb4b0 pc=0xd6d22d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x807de6?, {0x15f5f58?, 0xc00a5b0a80?}, {{0x15f0490, 0xc006204000}, {0x0, 0x1, 0x20000180, 0x2f}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x65 fp=0xc0059eb5a0 sp=0xc0059eb540 pc=0xd6f265
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc0086dbb00, {0x15f5f58, 0xc00a5b0a80}, {{0x15f0490, 0xc006204000}, {0x0, 0x1, 0x20000180, 0x2f}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0xa5 fp=0xc0059eb620 sp=0xc0059eb5a0 pc=0x7738a5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xb2e71c?, 0xc0086dbb00, {{0x15f0490, 0xc006204000}, {0x0, 0x1, 0x20000180, 0x2f}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x8e fp=0xc0059eb7f0 sp=0xc0059eb620 pc=0xb4196e
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc00a5b0a80, {{0x4}, {0x20000180}, {0x2f}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x25a fp=0xc0059eb930 sp=0xc0059eb7f0 pc=0xb4111a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc00a5b0a80, 0x1, {{0x4}, {0x20000180}, {0x2f}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc0059ebc70 sp=0xc0059eb930 pc=0x9cb66b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc00a5b0a80, 0x85?, {{0x4}, {0x20000180}, {0x2f}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x54 fp=0xc0059ebcd0 sp=0xc0059ebc70 pc=0x9ccc54
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0059ebd78?, 0x9829e6?, {{0x4}, {0x20000180}, {0x2f}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x85 fp=0xc0059ebd30 sp=0xc0059ebcd0 pc=0x9cc845
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00765de10?)
	pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc0059ebe28 sp=0xc0059ebd30 pc=0x9cc50c
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc00e05fc00?, 0xc00a5b0a80)
	pkg/sentry/kernel/task_run.go:265 +0x144a fp=0xc0059ebf60 sp=0xc0059ebe28 pc=0x9be14a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc00a5b0a80, 0x79e6)
	pkg/sentry/kernel/task_run.go:94 +0x21c fp=0xc0059ebfc0 sp=0xc0059ebf60 pc=0x9bc65c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc0059ebfe0 sp=0xc0059ebfc0 pc=0x9c9aea
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0059ebfe8 sp=0xc0059ebfe0 pc=0x46d401
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x105