panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x94b45d]

goroutine 1820535 [running]:
panic({0x10ec220, 0x1e67c20})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc002268ff0 sp=0xc002268f30 pc=0x436c1b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc002269050 sp=0xc002268ff0 pc=0x44e23d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x1ec6308?, 0xc0006561d2?)
	pkg/sentry/kernel/tty.go:54 +0x9d fp=0xc0022690e0 sp=0xc002269050 pc=0x94b45d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x1be, 0xc0061ca000, 0xc0061ca010, {0xc0006561c0?, 0xc009274200?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x34e fp=0xc002269308 sp=0xc0022690e0 pc=0xc896ae
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0061ca010, 0xc0056e0000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x99 fp=0xc002269370 sp=0xc002269308 pc=0xc8bf99
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0061ca010, {0x14c8e18, 0xc005e8ca80}, {{0x14c30d0, 0xc0056e0000}, {0x0, 0x1, 0x20000540, 0x1be}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x214 fp=0xc002269450 sp=0xc002269370 pc=0xc8b954
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0061ca000, {0x14c8e18?, 0xc005e8ca80?}, {{0x14c30d0, 0xc0056e0000}, {0x0, 0x1, 0x20000540, 0x1be}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xbf fp=0xc0022694d8 sp=0xc002269450 pc=0xc8881f
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x0?, {0x14c8e18?, 0xc005e8ca80?}, {{0x14c30d0, 0xc0056e0000}, {0x0, 0x1, 0x20000540, 0x1be}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x5b fp=0xc002269538 sp=0xc0022694d8 pc=0xc8a2db
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc006e29e00, {0x14c8e18, 0xc005e8ca80}, {{0x14c30d0, 0xc0056e0000}, {0x0, 0x1, 0x20000540, 0x1be}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x91 fp=0xc0022695b8 sp=0xc002269538 pc=0x73fa31
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xffffffff?, 0xc006e29e00, {{0x14c30d0, 0xc0056e0000}, {0x0, 0x1, 0x20000540, 0x1be}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x85 fp=0xc002269778 sp=0xc0022695b8 pc=0xa85ee5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc005e8ca80, {{0x6}, {0x20000540}, {0x1be}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x1c5 fp=0xc002269880 sp=0xc002269778 pc=0xa857c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc005e8ca80, 0x1, {{0x6}, {0x20000540}, {0x1be}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x755 fp=0xc002269c70 sp=0xc002269880 pc=0x942635
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc005e8ca80, 0x85?, {{0x6}, {0x20000540}, {0x1be}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4a fp=0xc002269cd0 sp=0xc002269c70 pc=0x94386a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0x8fa11a?, 0xc002321620?, {{0x6}, {0x20000540}, {0x1be}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc002269d30 sp=0xc002269cd0 pc=0x943545
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc006e672b0?)
	pkg/sentry/kernel/task_syscall.go:257 +0x2f0 fp=0xc002269e28 sp=0xc002269d30 pc=0x9432b0
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc006bb6000?, 0xc005e8ca80)
	pkg/sentry/kernel/task_run.go:265 +0x103e fp=0xc002269f60 sp=0xc002269e28 pc=0x9374de
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc005e8ca80, 0xa56)
	pkg/sentry/kernel/task_run.go:94 +0x1b8 fp=0xc002269fc0 sp=0xc002269f60 pc=0x935e78
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc002269fe0 sp=0xc002269fc0 pc=0x940e2a
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc002269fe8 sp=0xc002269fe0 pc=0x46d5e1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xef