panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0xc1680f]

goroutine 645203 [running]:
panic({0xfd4da0, 0x1d6aa20})
	GOROOT/src/runtime/panic.go:987 +0x3ba fp=0xc006a25fd0 sp=0xc006a25f10 pc=0x43761a
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:835 +0x2f6 fp=0xc006a26020 sp=0xc006a25fd0 pc=0x44e696
gvisor.dev/gvisor/pkg/tcpip/link/loopback.(*endpoint).WritePackets(0x0?, {{0xc00662caa8, 0x1, 0x1}})
	pkg/tcpip/link/loopback/loopback.go:96 +0x14f fp=0xc006a260c8 sp=0xc006a26020 pc=0xc1680f
gvisor.dev/gvisor/pkg/tcpip/link/nested.(*Endpoint).WritePackets(0xc0039c6a00?, {{0xc00662caa8?, 0x0?, 0x0?}})
	pkg/tcpip/link/nested/nested.go:117 +0x30 fp=0xc006a260f8 sp=0xc006a260c8 pc=0xa8c410
gvisor.dev/gvisor/pkg/tcpip/link/nested.(*Endpoint).WritePackets(...)
	pkg/tcpip/link/nested/nested.go:117
gvisor.dev/gvisor/pkg/tcpip/link/packetsocket.(*endpoint).WritePackets(0xc0039c6a00, {{0xc00662caa8, 0x1, 0x1}})
	pkg/tcpip/link/packetsocket/packetsocket.go:55 +0xc6 fp=0xc006a26140 sp=0xc006a260f8 pc=0xa8c9a6
gvisor.dev/gvisor/pkg/tcpip/stack.(*delegatingQueueingDiscipline).WritePacket(0xc005b294b0?, {0xc006a261d8?})
	pkg/tcpip/stack/nic.go:145 +0xca fp=0xc006a261b0 sp=0xc006a26140 pc=0x8e9a0a
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).writeRawPacket(0xc009c64000, {0x3e?})
	pkg/tcpip/stack/nic.go:391 +0x4a fp=0xc006a261e8 sp=0xc006a261b0 pc=0x8eb1ea
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).writePacket(0xc009c64000, {0x10?})
	pkg/tcpip/stack/nic.go:385 +0x47 fp=0xc006a26210 sp=0xc006a261e8 pc=0x8eb167
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).WritePacket(0xc009c64000, 0xffca?, {0x0?})
	pkg/tcpip/stack/nic.go:346 +0x1e5 fp=0xc006a26348 sp=0xc006a26210 pc=0x8eaf85
gvisor.dev/gvisor/pkg/tcpip/network/ipv6.(*endpoint).writePacket(0xc007556000, 0xc00360ec80, {0x0?}, 0x1152c65?, 0x0?)
	pkg/tcpip/network/ipv6/ipv6.go:863 +0x3fb fp=0xc006a265d0 sp=0xc006a26348 pc=0xa652bb
gvisor.dev/gvisor/pkg/tcpip/network/ipv6.(*endpoint).WritePacket(0xc007556000, 0xc00360ec80, {0x62c7c0?, 0xc0?, 0x0?}, {0x0?})
	pkg/tcpip/network/ipv6/ipv6.go:814 +0x238 fp=0xc006a26670 sp=0xc006a265d0 pc=0xa64db8
gvisor.dev/gvisor/pkg/tcpip/stack.(*Route).WritePacket(0xc00360ec80, {0x3e?, 0x0?, 0x0?}, {0xc00669ffb0?})
	pkg/tcpip/stack/route.go:495 +0x90 fp=0xc006a266b0 sp=0xc006a26670 pc=0x8f9870
gvisor.dev/gvisor/pkg/tcpip/transport/internal/network.(*WriteContext).WritePacket(0xc006a26830, {0x3e?}, 0x0)
	pkg/tcpip/transport/internal/network/endpoint.go:320 +0xf4 fp=0xc006a26700 sp=0xc006a266b0 pc=0x9ee1f4
gvisor.dev/gvisor/pkg/tcpip/transport/udp.(*endpoint).write(0xc007580000, {0x13704e8, 0xc0039c6b90}, {0xc00614d220, 0x0, 0x0, 0x0, {0x0, 0x0, 0x0, ...}})
	pkg/tcpip/transport/udp/endpoint.go:529 +0x537 fp=0xc006a27350 sp=0xc006a26700 pc=0xa82f77
gvisor.dev/gvisor/pkg/tcpip/transport/udp.(*endpoint).Write(0xc007580000, {0x13704e8?, 0xc0039c6b90?}, {0xc00614d220, 0x0, 0x0, 0x0, {0x0, 0x0, 0x0, ...}})
	pkg/tcpip/transport/udp/endpoint.go:366 +0x5c fp=0xc006a273a8 sp=0xc006a27350 pc=0xa81c5c
gvisor.dev/gvisor/pkg/sentry/socket/netstack.(*Socket).SendMsg(0xc003631b20, 0xc006158a80, {{0x1378058, 0xc007210000}, {0x0, 0x1, 0x20000040, 0xf2}, {0x0, 0x1}}, ...)
	pkg/sentry/socket/netstack/netstack.go:2936 +0x536 fp=0xc006a27610 sp=0xc006a273a8 pc=0xaa1156
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.sendTo(0xc006158a80, 0x1cb9958?, 0xc006198ba0?, 0xf2, 0x24040001, 0x20000140, 0x40000000?)
	pkg/sentry/syscalls/linux/sys_socket.go:1173 +0x5cc fp=0xc006a27900 sp=0xc006a27610 pc=0xb023ac
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.SendTo(0xc006158a80?, {{0x3}, {0x20000040}, {0xf2}, {0x24040001}, {0x20000140}, {0x1c}})
	pkg/sentry/syscalls/linux/sys_socket.go:1186 +0x85 fp=0xc006a27948 sp=0xc006a27900 pc=0xb027c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc006158a80, 0x2c, {{0x3}, {0x20000040}, {0xf2}, {0x24040001}, {0x20000140}, {0x1c}})
	pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc006a27c88 sp=0xc006a27948 pc=0x98dfcb
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc006158a80, 0x0?, {{0x3}, {0x20000040}, {0xf2}, {0x24040001}, {0x20000140}, {0x1c}})
	pkg/sentry/kernel/task_syscall.go:322 +0x54 fp=0xc006a27ce8 sp=0xc006a27c88 pc=0x98f5b4
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0003a8310?, 0xc006a27e30?, {{0x3}, {0x20000040}, {0xf2}, {0x24040001}, {0x20000140}, {0x1c}})
	pkg/sentry/kernel/task_syscall.go:282 +0x85 fp=0xc006a27d48 sp=0xc006a27ce8 pc=0x98f1a5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000c06370?)
	pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc006a27e40 sp=0xc006a27d48 pc=0x98ee6c
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc0098e5700?, 0xc006158a80)
	pkg/sentry/kernel/task_run.go:256 +0x1245 fp=0xc006a27f60 sp=0xc006a27e40 pc=0x980d25
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc006158a80, 0x3d08)
	pkg/sentry/kernel/task_run.go:94 +0x229 fp=0xc006a27fc0 sp=0xc006a27f60 pc=0x97f449
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc006a27fe0 sp=0xc006a27fc0 pc=0x98c44a
runtime.goexit()
	src/runtime/asm_amd64.s:1594 +0x1 fp=0xc006a27fe8 sp=0xc006a27fe0 pc=0x46c501
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x105