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

goroutine 644311 [running]:
panic({0xbc4dc0, 0x1939a60})
	GOROOT/src/runtime/panic.go:987 +0x3ac fp=0x4002d0cf50 sp=0x4002d0ce90 pc=0x4526c
runtime.panicmem()
	GOROOT/src/runtime/panic.go:260 +0x48 fp=0x4002d0cf70 sp=0x4002d0cf50 pc=0x43be8
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x214 fp=0x4002d0cfb0 sp=0x4002d0cf70 pc=0x5c9b4
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x199e1b0?, 0x40014ec254?)
	pkg/sentry/kernel/tty.go:54 +0xc4 fp=0x4002d0d050 sp=0x4002d0cfc0 pc=0x4f5264
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x78, 0x4001f28600, 0x4001f28610, {0x40014ec200?, 0x4009a5e1c0?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x2bc fp=0x4002d0d280 sp=0x4002d0d050 pc=0x7d773c
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0x4001f28610, 0xfbb738?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xb4 fp=0x4002d0d2f0 sp=0x4002d0d280 pc=0x7d9cc4
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0x4001f28610, {0xfbb738, 0x4006687500}, {{0xfb5d68, 0x4008390000}, {0x0, 0x1, 0x20008400, 0x78}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1d8 fp=0x4002d0d3d0 sp=0x4002d0d2f0 pc=0x7d9658
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0x4001f28600, {0xfbb738?, 0x4006687500?}, {{0xfb5d68, 0x4008390000}, {0x0, 0x1, 0x20008400, 0x78}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xd4 fp=0x4002d0d460 sp=0x4002d0d3d0 pc=0x7d69c4
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x4008390000?, {0xfbb738?, 0x4006687500?}, {{0xfb5d68, 0x4008390000}, {0x0, 0x1, 0x20008400, 0x78}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x64 fp=0x4002d0d4c0 sp=0x4002d0d460 pc=0x7d81d4
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0x40010c0680, {0xfbb738, 0x4006687500}, {{0xfb5d68, 0x4008390000}, {0x0, 0x1, 0x20008400, 0x78}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x80 fp=0x4002d0d540 sp=0x4002d0d4c0 pc=0x3183d0
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x0?, 0x40010c0680, {{0xfb5d68, 0x4008390000}, {0x0, 0x1, 0x20008400, 0x78}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x88 fp=0x4002d0d700 sp=0x4002d0d540 pc=0x60e578
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0x4006687500, {{0x4}, {0x20008400}, {0x78}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x134 fp=0x4002d0d840 sp=0x4002d0d700 pc=0x60df34
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0x4006687500, 0x40, {{0x4}, {0x20008400}, {0x78}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x5a0 fp=0x4002d0dc30 sp=0x4002d0d840 pc=0x4ed030
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0x4006687500, 0x0?, {{0x4}, {0x20008400}, {0x78}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x3c fp=0x4002d0dc90 sp=0x4002d0dc30 pc=0x4edf2c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0x400a7205e8?, 0x1c62c?, {{0x4}, {0x20008400}, {0x78}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x58 fp=0x4002d0dcf0 sp=0x4002d0dc90 pc=0x4edc48
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0x400b2191e0?)
	pkg/sentry/kernel/task_syscall.go:257 +0x284 fp=0x4002d0ddf0 sp=0x4002d0dcf0 pc=0x4ed9f4
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x4007b13b80?, 0x4006687500)
	pkg/sentry/kernel/task_run.go:265 +0xdbc fp=0x4002d0df40 sp=0x4002d0ddf0 pc=0x4e31dc
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0x4006687500, 0x7c8b)
	pkg/sentry/kernel/task_run.go:94 +0x190 fp=0x4002d0dfb0 sp=0x4002d0df40 pc=0x4e1e40
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2c fp=0x4002d0dfd0 sp=0x4002d0dfb0 pc=0x4ebaec
runtime.goexit()
	src/runtime/asm_arm64.s:1172 +0x4 fp=0x4002d0dfd0 sp=0x4002d0dfd0 pc=0x7a604
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xe4