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

goroutine 167 [running]:
panic({0x319320, 0x26ce990})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc000ca8ab0 sp=0xc000ca89f0 pc=0x11b33fb
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc000ca8b10 sp=0xc000ca8ab0 pc=0x11cc2bd
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc000ca8cc0)
	pkg/sentry/kernel/sessions.go:237 +0x6d fp=0xc000ca8c48 sp=0xc000ca8b10 pc=0x1a90c6d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x0, 0xc0003ce000, 0xc0003ce010, {0xc000327e60, 0x11c, 0x11c})
	pkg/sentry/fsimpl/devpts/line_discipline.go:404 +0x73b fp=0xc000ca8e98 sp=0xc000ca8c48 pc=0x2075f1b
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0003ce010, 0xc00025b500?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x1e2 fp=0xc000ca8f48 sp=0xc000ca8e98 pc=0x207a762
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0003ce010, {0x742e58, 0xc00025b500}, {{0x73d390, 0xc000979000}, {0x0, 0x1, 0x200001c0, 0x11c}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x2e5 fp=0xc000ca9098 sp=0xc000ca8f48 pc=0x2079c25
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0003ce000, {0x742e58, 0xc00025b500}, {{0x73d390, 0xc000979000}, {0x0, 0x1, 0x200001c0, 0x11c}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xd7 fp=0xc000ca9130 sp=0xc000ca9098 pc=0x2074397
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc0006b8680, {0x742e58, 0xc00025b500}, {{0x73d390, 0xc000979000}, {0x0, 0x1, 0x200001c0, 0x11c}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0xd6 fp=0xc000ca91b0 sp=0xc000ca9130 pc=0x20776f6
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc0006b8680, {0x742e58, 0xc00025b500}, {{0x73d390, 0xc000979000}, {0x0, 0x1, 0x200001c0, 0x11c}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x152 fp=0xc000ca9278 sp=0xc000ca91b0 pc=0x1729b72
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x0?, 0x1ce4740?, {{0x73d390, 0xc000979000}, {0x0, 0x1, 0x200001c0, 0x11c}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0xae fp=0xc000ca9408 sp=0xc000ca9278 pc=0x1d1368e
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc00025b500, {{0x3}, {0x200001c0}, {0x11c}, {0x7f4d54ce0750}, {0x7f4d54ce0e78}, {0x7f4d54ce0e78}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x34f fp=0xc000ca95a8 sp=0xc000ca9408 pc=0x1d12c2f
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc00025b500, 0x1, {{0x3}, {0x200001c0}, {0x11c}, {0x7f4d54ce0750}, {0x7f4d54ce0e78}, {0x7f4d54ce0e78}})
	pkg/sentry/kernel/task_syscall.go:142 +0xab7 fp=0xc000ca99c0 sp=0xc000ca95a8 pc=0x1ad8477
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc00025b500, 0x1?, {{0x3}, {0x200001c0}, {0x11c}, {0x7f4d54ce0750}, {0x7f4d54ce0e78}, {0x7f4d54ce0e78}})
	pkg/sentry/kernel/task_syscall.go:322 +0x8e fp=0xc000ca9a60 sp=0xc000ca99c0 pc=0x1ada58e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0000025a0?, 0xc000ca9b8f?, {{0x3}, {0x200001c0}, {0x11c}, {0x7f4d54ce0750}, {0x7f4d54ce0e78}, {0x7f4d54ce0e78}})
	pkg/sentry/kernel/task_syscall.go:282 +0xc5 fp=0xc000ca9ad8 sp=0xc000ca9a60 pc=0x1ad9e85
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00025b500)
	pkg/sentry/kernel/task_syscall.go:257 +0x53b fp=0xc000ca9c00 sp=0xc000ca9ad8 pc=0x1ad999b
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc00025b500?, 0xc00025b500)
	pkg/sentry/kernel/task_run.go:265 +0x22b4 fp=0xc000ca9ec0 sp=0xc000ca9c00 pc=0x1ac2714
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc00025b500, 0xd)
	pkg/sentry/kernel/task_run.go:94 +0x2cc fp=0xc000ca9fb0 sp=0xc000ca9ec0 pc=0x1abfa8c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x48 fp=0xc000ca9fe0 sp=0xc000ca9fb0 pc=0x1ad5b68
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc000ca9fe8 sp=0xc000ca9fe0 pc=0x11ec2a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x1da