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

goroutine 5927 [running]:
panic({0x11ef240, 0x210de40})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc001edb018 sp=0xc001edaf58 pc=0x436a3b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc001edb078 sp=0xc001edb018 pc=0x44e05d
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc001edb2e8)
	pkg/sentry/kernel/sessions.go:237 +0x5a fp=0xc001edb168 sp=0xc001edb078 pc=0x99ed1a
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x6bdc5a, 0xc00032e180, 0xc00032e190, {0xc002436000?, 0xc001d69500?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:400 +0x445 fp=0xc001edb398 sp=0xc001edb168 pc=0xd6e1c5
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc00032e190, 0xc001d69500?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xce fp=0xc001edb400 sp=0xc001edb398 pc=0xd7104e
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc00032e190, {0x15f7018, 0xc001d69500}, {{0x15f1550, 0xc0023a4000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1f9 fp=0xc001edb4b0 sp=0xc001edb400 pc=0xd70919
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc00032e180, {0x15f7018, 0xc001d69500}, {{0x15f1550, 0xc0023a4000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xcd fp=0xc001edb540 sp=0xc001edb4b0 pc=0xd6d00d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x3?, {0x15f7018?, 0xc001d69500?}, {{0x15f1550, 0xc0023a4000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x65 fp=0xc001edb5a0 sp=0xc001edb540 pc=0xd6f045
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc002492180, {0x15f7018, 0xc001d69500}, {{0x15f1550, 0xc0023a4000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0xa5 fp=0xc001edb620 sp=0xc001edb5a0 pc=0x7738a5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xb2e4cf?, 0xc002492180, {{0x15f1550, 0xc0023a4000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x8e fp=0xc001edb7f0 sp=0xc001edb620 pc=0xb416ae
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc001d69500, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x25a fp=0xc001edb930 sp=0xc001edb7f0 pc=0xb40e5a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc001d69500, 0x1, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc001edbc70 sp=0xc001edb930 pc=0x9cb66b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc001d69500, 0x0?, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x54 fp=0xc001edbcd0 sp=0xc001edbc70 pc=0x9ccc54
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc000148040?, 0xc001edbe18?, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x85 fp=0xc001edbd30 sp=0xc001edbcd0 pc=0x9cc845
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000929d90?)
	pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc001edbe28 sp=0xc001edbd30 pc=0x9cc50c
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc001fbbc00?, 0xc001d69500)
	pkg/sentry/kernel/task_run.go:265 +0x144a fp=0xc001edbf60 sp=0xc001edbe28 pc=0x9be14a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc001d69500, 0x193)
	pkg/sentry/kernel/task_run.go:94 +0x21c fp=0xc001edbfc0 sp=0xc001edbf60 pc=0x9bc65c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc001edbfe0 sp=0xc001edbfc0 pc=0x9c9aea
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc001edbfe8 sp=0xc001edbfe0 pc=0x46d401
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x105