panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x91d130]

goroutine 4793708 [running]:
panic({0x10ec200, 0x1e68c20})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc000fdcf90 sp=0xc000fdced0 pc=0x436c1b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc000fdcff0 sp=0xc000fdcf90 pc=0x44e23d
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc000fdd1e0)
	pkg/sentry/kernel/sessions.go:237 +0x50 fp=0xc000fdd0e0 sp=0xc000fdcff0 pc=0x91d130
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0xcd, 0xc0027a6300, 0xc0027a6310, {0xc001e96750?, 0xc0009c3df0?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:402 +0x2eb fp=0xc000fdd308 sp=0xc000fdd0e0 pc=0xc8946b
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0027a6310, 0xc0089a9000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x99 fp=0xc000fdd370 sp=0xc000fdd308 pc=0xc8bd79
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0027a6310, {0x14c8ed8, 0xc003a10000}, {{0x14c3190, 0xc0089a9000}, {0x0, 0x1, 0x20000040, 0xcd}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x214 fp=0xc000fdd450 sp=0xc000fdd370 pc=0xc8b734
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0027a6300, {0x14c8ed8?, 0xc003a10000?}, {{0x14c3190, 0xc0089a9000}, {0x0, 0x1, 0x20000040, 0xcd}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xbf fp=0xc000fdd4d8 sp=0xc000fdd450 pc=0xc8863f
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x90bf57?, {0x14c8ed8?, 0xc003a10000?}, {{0x14c3190, 0xc0089a9000}, {0x0, 0x1, 0x20000040, 0xcd}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x5b fp=0xc000fdd538 sp=0xc000fdd4d8 pc=0xc8a0fb
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc008b7b180, {0x14c8ed8, 0xc003a10000}, {{0x14c3190, 0xc0089a9000}, {0x0, 0x1, 0x20000040, 0xcd}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x91 fp=0xc000fdd5b8 sp=0xc000fdd538 pc=0x73fa31
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xffffffff?, 0xc008b7b180, {{0x14c3190, 0xc0089a9000}, {0x0, 0x1, 0x20000040, 0xcd}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x85 fp=0xc000fdd778 sp=0xc000fdd5b8 pc=0xa85c65
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc003a10000, {{0x3}, {0x20000040}, {0xcd}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x1c5 fp=0xc000fdd880 sp=0xc000fdd778 pc=0xa85545
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc003a10000, 0x1, {{0x3}, {0x20000040}, {0xcd}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x755 fp=0xc000fddc70 sp=0xc000fdd880 pc=0x942635
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc003a10000, 0x0?, {{0x3}, {0x20000040}, {0xcd}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4a fp=0xc000fddcd0 sp=0xc000fddc70 pc=0x94386a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc00020db00?, 0xc000fdde18?, {{0x3}, {0x20000040}, {0xcd}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc000fddd30 sp=0xc000fddcd0 pc=0x943545
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc006fb9810?)
	pkg/sentry/kernel/task_syscall.go:257 +0x2f0 fp=0xc000fdde28 sp=0xc000fddd30 pc=0x9432b0
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc008b7b100?, 0xc003a10000)
	pkg/sentry/kernel/task_run.go:265 +0x103e fp=0xc000fddf60 sp=0xc000fdde28 pc=0x9374de
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc003a10000, 0x56cb)
	pkg/sentry/kernel/task_run.go:94 +0x1b8 fp=0xc000fddfc0 sp=0xc000fddf60 pc=0x935e78
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc000fddfe0 sp=0xc000fddfc0 pc=0x940e2a
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc000fddfe8 sp=0xc000fddfe0 pc=0x46d5e1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xef