panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1966568]

goroutine 53549 [running]:
panic({0x317be0, 0x22791d0})
	GOROOT/src/runtime/panic.go:987 +0x3ac fp=0xc00a4488e0 sp=0xc00a448820 pc=0x128054c
runtime.panicmem()
	GOROOT/src/runtime/panic.go:260 +0x48 fp=0xc00a448900 sp=0xc00a4488e0 pc=0x127eec8
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x214 fp=0xc00a448940 sp=0xc00a448900 pc=0x1299094
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0xc005368528, 0x1?)
	pkg/sentry/kernel/tty.go:54 +0x88 fp=0xc00a448a40 sp=0xc00a448950 pc=0x1966568
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x21c2b00, 0xc009d56000, 0xc009d56010, {0xc0002246c0, 0x235, 0x235})
	pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x308 fp=0xc00a448c90 sp=0xc00a448a40 pc=0x1d87dd8
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc009d56010, 0x8500d8?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x14c fp=0xc00a448d40 sp=0xc00a448c90 pc=0x1d8b21c
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc009d56010, {0x8500d8, 0xc00727a000}, {{0x84a708, 0xc006e76000}, {0x0, 0x1, 0x20002d80, 0x235}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1b0 fp=0xc00a448e80 sp=0xc00a448d40 pc=0x1d8a9e0
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc009d56000, {0x8500d8, 0xc00727a000}, {{0x84a708, 0xc006e76000}, {0x0, 0x1, 0x20002d80, 0x235}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xb8 fp=0xc00a448f50 sp=0xc00a448e80 pc=0x1d86d88
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc002217400, {0x8500d8, 0xc00727a000}, {{0x84a708, 0xc006e76000}, {0x0, 0x1, 0x20002d80, 0x235}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0xcc fp=0xc00a449010 sp=0xc00a448f50 pc=0x1d8906c
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc002217400, {0x8500d8, 0xc00727a000}, {{0x84a708, 0xc006e76000}, {0x0, 0x1, 0x20002d80, 0x235}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0xdc fp=0xc00a4490e0 sp=0xc00a449010 pc=0x16bbabc
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xc00727a000?, 0xc002217400, {{0x84a708, 0xc006e76000}, {0x0, 0x1, 0x20002d80, 0x235}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0xc4 fp=0xc00a449340 sp=0xc00a4490e0 pc=0x1af6504
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc00727a000, {{0x7}, {0x20002d80}, {0x235}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x198 fp=0xc00a4494e0 sp=0xc00a449340 pc=0x1af5e38
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc00727a000, 0x40, {{0x7}, {0x20002d80}, {0x235}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x6f4 fp=0xc00a4499d0 sp=0xc00a4494e0 pc=0x195a9b4
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc00727a000, 0x125160c?, {{0x7}, {0x20002d80}, {0x235}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x50 fp=0xc00a449a70 sp=0xc00a4499d0 pc=0x195c020
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc00a449b38?, 0x12b8888?, {{0x7}, {0x20002d80}, {0x235}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x78 fp=0xc00a449af0 sp=0xc00a449a70 pc=0x195bb48
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00727a000)
	pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc00a449c20 sp=0xc00a449af0 pc=0x195b7ec
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc00727a000?, 0xc00727a000)
	pkg/sentry/kernel/task_run.go:265 +0x13f0 fp=0xc00a449eb0 sp=0xc00a449c20 pc=0x194b660
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc00727a000, 0x2118)
	pkg/sentry/kernel/task_run.go:94 +0x2a0 fp=0xc00a449fa0 sp=0xc00a449eb0 pc=0x1949b00
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x44 fp=0xc00a449fd0 sp=0xc00a449fa0 pc=0x1958d84
runtime.goexit()
	src/runtime/asm_arm64.s:1172 +0x4 fp=0xc00a449fd0 sp=0xc00a449fd0 pc=0x12b7704
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x180