panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1ae2d4d]

goroutine 4631108 [running]:
panic({0x3192e0, 0x2647070})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0020bca08 sp=0xc0020bc948 pc=0x125ea7b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0020bca68 sp=0xc0020bca08 pc=0x127793d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0xc00155e1c8, 0x1?)
	pkg/sentry/kernel/tty.go:54 +0xcd fp=0xc0020bcb58 sp=0xc0020bca68 pc=0x1ae2d4d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x123540a, 0xc000df6480, 0xc000df6490, {0xc00180a3f0, 0x8b, 0x8b})
	pkg/sentry/fsimpl/devpts/line_discipline.go:409 +0x4d6 fp=0xc0020bcdb0 sp=0xc0020bcb58 pc=0x1ffced6
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc000df6490, 0xc004820000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x19f fp=0xc0020bce60 sp=0xc0020bcdb0 pc=0x200117f
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc000df6490, {0x819e18, 0xc00830a000}, {{0x8140d0, 0xc004820000}, {0x0, 0x1, 0x20000080, 0x8b}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x269 fp=0xc0020bcf98 sp=0xc0020bce60 pc=0x2000729
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc000df6480, {0x819e18, 0xc00830a000}, {{0x8140d0, 0xc004820000}, {0x0, 0x1, 0x20000080, 0x8b}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xc6 fp=0xc0020bd030 sp=0xc0020bcf98 pc=0x1ffba46
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc006bcc680, {0x819e18, 0xc00830a000}, {{0x8140d0, 0xc004820000}, {0x0, 0x1, 0x20000080, 0x8b}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0xc5 fp=0xc0020bd0b0 sp=0xc0020bd030 pc=0x1ffe525
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc006bcc680, {0x819e18, 0xc00830a000}, {{0x8140d0, 0xc004820000}, {0x0, 0x1, 0x20000080, 0x8b}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x125 fp=0xc0020bd180 sp=0xc0020bd0b0 pc=0x178d5c5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xffffffff?, 0xc006bcc680, {{0x8140d0, 0xc004820000}, {0x0, 0x1, 0x20000080, 0x8b}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x9d fp=0xc0020bd370 sp=0xc0020bd180 pc=0x1cdc7dd
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc00830a000, {{0x3}, {0x20000080}, {0x8b}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x275 fp=0xc0020bd4d8 sp=0xc0020bd370 pc=0x1cdbe95
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc00830a000, 0x1, {{0x3}, {0x20000080}, {0x8b}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x9b9 fp=0xc0020bd9b8 sp=0xc0020bd4d8 pc=0x1ad3cd9
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc00830a000, 0x0?, {{0x3}, {0x20000080}, {0x8b}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x7d fp=0xc0020bda50 sp=0xc0020bd9b8 pc=0x1ad5abd
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0063d8820?, 0xc000225e00?, {{0x3}, {0x20000080}, {0x8b}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x8f fp=0xc0020bdac8 sp=0xc0020bda50 pc=0x1ad546f
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00830a000)
	pkg/sentry/kernel/task_syscall.go:257 +0x4c5 fp=0xc0020bdbf0 sp=0xc0020bdac8 pc=0x1ad5005
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc00830a000?, 0xc00830a000)
	pkg/sentry/kernel/task_run.go:265 +0x1d4b fp=0xc0020bdec8 sp=0xc0020bdbf0 pc=0x1abfa4b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc00830a000, 0x7316)
	pkg/sentry/kernel/task_run.go:94 +0x36b fp=0xc0020bdfb0 sp=0xc0020bdec8 pc=0x1abd36b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x48 fp=0xc0020bdfe0 sp=0xc0020bdfb0 pc=0x1ad17e8
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0020bdfe8 sp=0xc0020bdfe0 pc=0x1297921
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x1ad