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

goroutine 1681 [running]:
panic({0x10ec220, 0x1e67c20})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc001248ff0 sp=0xc001248f30 pc=0x436c1b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc001249050 sp=0xc001248ff0 pc=0x44e23d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x1ec6308?, 0xc00033bbb7?)
	pkg/sentry/kernel/tty.go:54 +0x9d fp=0xc0012490e0 sp=0xc001249050 pc=0x94b45d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x6, 0xc0002ba180, 0xc0002ba190, {0xc00033bbb2?, 0xc00058c8a0?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x34e fp=0xc001249308 sp=0xc0012490e0 pc=0xc896ae
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0002ba190, 0xc000fdb000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x99 fp=0xc001249370 sp=0xc001249308 pc=0xc8bf99
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0002ba190, {0x14c8e18, 0xc000f3ea80}, {{0x14c30d0, 0xc000fdb000}, {0x0, 0x1, 0x20000040, 0x6}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x214 fp=0xc001249450 sp=0xc001249370 pc=0xc8b954
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0002ba180, {0x14c8e18?, 0xc000f3ea80?}, {{0x14c30d0, 0xc000fdb000}, {0x0, 0x1, 0x20000040, 0x6}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xbf fp=0xc0012494d8 sp=0xc001249450 pc=0xc8881f
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x0?, {0x14c8e18?, 0xc000f3ea80?}, {{0x14c30d0, 0xc000fdb000}, {0x0, 0x1, 0x20000040, 0x6}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x5b fp=0xc001249538 sp=0xc0012494d8 pc=0xc8a2db
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc000576f00, {0x14c8e18, 0xc000f3ea80}, {{0x14c30d0, 0xc000fdb000}, {0x0, 0x1, 0x20000040, 0x6}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x91 fp=0xc0012495b8 sp=0xc001249538 pc=0x73fa31
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xffffffff?, 0xc000576f00, {{0x14c30d0, 0xc000fdb000}, {0x0, 0x1, 0x20000040, 0x6}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x85 fp=0xc001249778 sp=0xc0012495b8 pc=0xa85ee5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc000f3ea80, {{0x3}, {0x20000040}, {0x6}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x1c5 fp=0xc001249880 sp=0xc001249778 pc=0xa857c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc000f3ea80, 0x1, {{0x3}, {0x20000040}, {0x6}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x755 fp=0xc001249c70 sp=0xc001249880 pc=0x942635
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc000f3ea80, 0x85?, {{0x3}, {0x20000040}, {0x6}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4a fp=0xc001249cd0 sp=0xc001249c70 pc=0x94386a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0x8fa11a?, 0xc000030620?, {{0x3}, {0x20000040}, {0x6}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc001249d30 sp=0xc001249cd0 pc=0x943545
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc0004f7860?)
	pkg/sentry/kernel/task_syscall.go:257 +0x2f0 fp=0xc001249e28 sp=0xc001249d30 pc=0x9432b0
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc000576e00?, 0xc000f3ea80)
	pkg/sentry/kernel/task_run.go:265 +0x103e fp=0xc001249f60 sp=0xc001249e28 pc=0x9374de
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc000f3ea80, 0xc2)
	pkg/sentry/kernel/task_run.go:94 +0x1b8 fp=0xc001249fc0 sp=0xc001249f60 pc=0x935e78
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc001249fe0 sp=0xc001249fc0 pc=0x940e2a
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc001249fe8 sp=0xc001249fe0 pc=0x46d5e1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xef