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

goroutine 144 [running]:
panic({0x319320, 0x26ce990})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0005eaab0 sp=0xc0005ea9f0 pc=0x11b33fb
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0005eab10 sp=0xc0005eaab0 pc=0x11cc2bd
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc0005ead40)
	pkg/sentry/kernel/sessions.go:237 +0x6d fp=0xc0005eac48 sp=0xc0005eab10 pc=0x1a90c6d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x0, 0xc00036c000, 0xc00036c010, {0xc00023cb40, 0x41, 0x41})
	pkg/sentry/fsimpl/devpts/line_discipline.go:402 +0x665 fp=0xc0005eae98 sp=0xc0005eac48 pc=0x2075e45
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc00036c010, 0xc000993500?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x1e2 fp=0xc0005eaf48 sp=0xc0005eae98 pc=0x207a762
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc00036c010, {0x742e58, 0xc000993500}, {{0x73d390, 0xc000882000}, {0x0, 0x1, 0x20000040, 0x41}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x2e5 fp=0xc0005eb098 sp=0xc0005eaf48 pc=0x2079c25
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc00036c000, {0x742e58, 0xc000993500}, {{0x73d390, 0xc000882000}, {0x0, 0x1, 0x20000040, 0x41}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xd7 fp=0xc0005eb130 sp=0xc0005eb098 pc=0x2074397
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc000202d80, {0x742e58, 0xc000993500}, {{0x73d390, 0xc000882000}, {0x0, 0x1, 0x20000040, 0x41}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0xd6 fp=0xc0005eb1b0 sp=0xc0005eb130 pc=0x20776f6
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc000202d80, {0x742e58, 0xc000993500}, {{0x73d390, 0xc000882000}, {0x0, 0x1, 0x20000040, 0x41}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x152 fp=0xc0005eb278 sp=0xc0005eb1b0 pc=0x1729b72
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x0?, 0x1ce4740?, {{0x73d390, 0xc000882000}, {0x0, 0x1, 0x20000040, 0x41}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0xae fp=0xc0005eb408 sp=0xc0005eb278 pc=0x1d1368e
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc000993500, {{0x3}, {0x20000040}, {0x41}, {0x7f9ecf72f750}, {0x7f9ecf72fe78}, {0x7f9ecf72fe78}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x34f fp=0xc0005eb5a8 sp=0xc0005eb408 pc=0x1d12c2f
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc000993500, 0x1, {{0x3}, {0x20000040}, {0x41}, {0x7f9ecf72f750}, {0x7f9ecf72fe78}, {0x7f9ecf72fe78}})
	pkg/sentry/kernel/task_syscall.go:142 +0xab7 fp=0xc0005eb9c0 sp=0xc0005eb5a8 pc=0x1ad8477
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc000993500, 0x1?, {{0x3}, {0x20000040}, {0x41}, {0x7f9ecf72f750}, {0x7f9ecf72fe78}, {0x7f9ecf72fe78}})
	pkg/sentry/kernel/task_syscall.go:322 +0x8e fp=0xc0005eba60 sp=0xc0005eb9c0 pc=0x1ada58e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc000768000?, 0xc0005ebb8f?, {{0x3}, {0x20000040}, {0x41}, {0x7f9ecf72f750}, {0x7f9ecf72fe78}, {0x7f9ecf72fe78}})
	pkg/sentry/kernel/task_syscall.go:282 +0xc5 fp=0xc0005ebad8 sp=0xc0005eba60 pc=0x1ad9e85
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000993500)
	pkg/sentry/kernel/task_syscall.go:257 +0x53b fp=0xc0005ebc00 sp=0xc0005ebad8 pc=0x1ad999b
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc000993500?, 0xc000993500)
	pkg/sentry/kernel/task_run.go:265 +0x22b4 fp=0xc0005ebec0 sp=0xc0005ebc00 pc=0x1ac2714
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc000993500, 0xe)
	pkg/sentry/kernel/task_run.go:94 +0x2cc fp=0xc0005ebfb0 sp=0xc0005ebec0 pc=0x1abfa8c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x48 fp=0xc0005ebfe0 sp=0xc0005ebfb0 pc=0x1ad5b68
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0005ebfe8 sp=0xc0005ebfe0 pc=0x11ec2a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x1da