panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1a90c6d]

goroutine 160 [running]:
panic({0x319320, 0x26ce990})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc000892ab0 sp=0xc0008929f0 pc=0x11b33fb
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc000892b10 sp=0xc000892ab0 pc=0x11cc2bd
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc000892dc0)
	pkg/sentry/kernel/sessions.go:237 +0x6d fp=0xc000892c48 sp=0xc000892b10 pc=0x1a90c6d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x0, 0xc000340000, 0xc000340010, {0xc000020d50, 0x21, 0x21})
	pkg/sentry/fsimpl/devpts/line_discipline.go:400 +0x585 fp=0xc000892e98 sp=0xc000892c48 pc=0x2075d65
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc000340010, 0xc000ad8000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x1e2 fp=0xc000892f48 sp=0xc000892e98 pc=0x207a762
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc000340010, {0x742e58, 0xc000ad8000}, {{0x73d390, 0xc000912000}, {0x0, 0x1, 0x20000040, 0x21}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x2e5 fp=0xc000893098 sp=0xc000892f48 pc=0x2079c25
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc000340000, {0x742e58, 0xc000ad8000}, {{0x73d390, 0xc000912000}, {0x0, 0x1, 0x20000040, 0x21}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xd7 fp=0xc000893130 sp=0xc000893098 pc=0x2074397
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc00079e600, {0x742e58, 0xc000ad8000}, {{0x73d390, 0xc000912000}, {0x0, 0x1, 0x20000040, 0x21}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0xd6 fp=0xc0008931b0 sp=0xc000893130 pc=0x20776f6
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc00079e600, {0x742e58, 0xc000ad8000}, {{0x73d390, 0xc000912000}, {0x0, 0x1, 0x20000040, 0x21}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x152 fp=0xc000893278 sp=0xc0008931b0 pc=0x1729b72
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x0?, 0x1ce4740?, {{0x73d390, 0xc000912000}, {0x0, 0x1, 0x20000040, 0x21}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0xae fp=0xc000893408 sp=0xc000893278 pc=0x1d1368e
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc000ad8000, {{0x3}, {0x20000040}, {0x21}, {0x7faa6a692750}, {0x7faa6a692e78}, {0x7faa6a692e78}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x34f fp=0xc0008935a8 sp=0xc000893408 pc=0x1d12c2f
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc000ad8000, 0x1, {{0x3}, {0x20000040}, {0x21}, {0x7faa6a692750}, {0x7faa6a692e78}, {0x7faa6a692e78}})
	pkg/sentry/kernel/task_syscall.go:142 +0xab7 fp=0xc0008939c0 sp=0xc0008935a8 pc=0x1ad8477
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc000ad8000, 0x1?, {{0x3}, {0x20000040}, {0x21}, {0x7faa6a692750}, {0x7faa6a692e78}, {0x7faa6a692e78}})
	pkg/sentry/kernel/task_syscall.go:322 +0x8e fp=0xc000893a60 sp=0xc0008939c0 pc=0x1ada58e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc000904000?, 0xc000893b8f?, {{0x3}, {0x20000040}, {0x21}, {0x7faa6a692750}, {0x7faa6a692e78}, {0x7faa6a692e78}})
	pkg/sentry/kernel/task_syscall.go:282 +0xc5 fp=0xc000893ad8 sp=0xc000893a60 pc=0x1ad9e85
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000ad8000)
	pkg/sentry/kernel/task_syscall.go:257 +0x53b fp=0xc000893c00 sp=0xc000893ad8 pc=0x1ad999b
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc000ad8000?, 0xc000ad8000)
	pkg/sentry/kernel/task_run.go:265 +0x22b4 fp=0xc000893ec0 sp=0xc000893c00 pc=0x1ac2714
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc000ad8000, 0xf)
	pkg/sentry/kernel/task_run.go:94 +0x2cc fp=0xc000893fb0 sp=0xc000893ec0 pc=0x1abfa8c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x48 fp=0xc000893fe0 sp=0xc000893fb0 pc=0x1ad5b68
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc000893fe8 sp=0xc000893fe0 pc=0x11ec2a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x1da