panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x99ed1a]

goroutine 1607997 [running]:
panic({0x11ef240, 0x210de40})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0018ff018 sp=0xc0018fef58 pc=0x436a3b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0018ff078 sp=0xc0018ff018 pc=0x44e05d
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc0018ff1e8)
	pkg/sentry/kernel/sessions.go:237 +0x5a fp=0xc0018ff168 sp=0xc0018ff078 pc=0x99ed1a
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x6bdc5a, 0xc0003aa180, 0xc0003aa190, {0xc009cea000?, 0xc006fac000?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:404 +0x34c fp=0xc0018ff398 sp=0xc0018ff168 pc=0xd6e0cc
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0003aa190, 0xc006fac000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xce fp=0xc0018ff400 sp=0xc0018ff398 pc=0xd7104e
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0003aa190, {0x15f7018, 0xc006fac000}, {{0x15f1550, 0xc004fde000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1f9 fp=0xc0018ff4b0 sp=0xc0018ff400 pc=0xd70919
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0003aa180, {0x15f7018, 0xc006fac000}, {{0x15f1550, 0xc004fde000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xcd fp=0xc0018ff540 sp=0xc0018ff4b0 pc=0xd6d00d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x3?, {0x15f7018?, 0xc006fac000?}, {{0x15f1550, 0xc004fde000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x65 fp=0xc0018ff5a0 sp=0xc0018ff540 pc=0xd6f045
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc0060af280, {0x15f7018, 0xc006fac000}, {{0x15f1550, 0xc004fde000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0xa5 fp=0xc0018ff620 sp=0xc0018ff5a0 pc=0x7738a5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xb2e4cf?, 0xc0060af280, {{0x15f1550, 0xc004fde000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x8e fp=0xc0018ff7f0 sp=0xc0018ff620 pc=0xb416ae
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc006fac000, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x25a fp=0xc0018ff930 sp=0xc0018ff7f0 pc=0xb40e5a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc006fac000, 0x1, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc0018ffc70 sp=0xc0018ff930 pc=0x9cb66b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc006fac000, 0x0?, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x54 fp=0xc0018ffcd0 sp=0xc0018ffc70 pc=0x9ccc54
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0003da310?, 0xc0018ffe18?, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x85 fp=0xc0018ffd30 sp=0xc0018ffcd0 pc=0x9cc845
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc005a29600?)
	pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc0018ffe28 sp=0xc0018ffd30 pc=0x9cc50c
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc0060af180?, 0xc006fac000)
	pkg/sentry/kernel/task_run.go:265 +0x144a fp=0xc0018fff60 sp=0xc0018ffe28 pc=0x9be14a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc006fac000, 0xa181)
	pkg/sentry/kernel/task_run.go:94 +0x21c fp=0xc0018fffc0 sp=0xc0018fff60 pc=0x9bc65c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc0018fffe0 sp=0xc0018fffc0 pc=0x9c9aea
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0018fffe8 sp=0xc0018fffe0 pc=0x46d401
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x105