syzbot

panic: interface conversion: stack.TransportEndpoint is nil, not *tcp.endpoint

goroutine 88457 [running]:
panic(0x10d3500, 0xc002425a70)
	GOROOT/src/runtime/panic.go:1065 +0x565 fp=0xc0836878a8 sp=0xc0836877e0 pc=0x437c65
runtime.panicdottypeE(...)
	GOROOT/src/runtime/iface.go:261
runtime.panicdottypeI(0x0, 0x126a740, 0x1109f00)
	GOROOT/src/runtime/iface.go:271 +0xcc fp=0xc0836878d0 sp=0xc0836878a8 pc=0x40b2ec
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*dispatcher).queuePacket(0xc0002266c0, 0x0, 0x0, 0x0, 0x0, 0x4, 0x5079, 0x0, 0x0, 0x13ee8b8, ...)
	pkg/tcpip/transport/tcp/dispatcher.go:178 +0x3aa fp=0xc08368a038 sp=0xc0836878d0 pc=0xacabca
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*protocol).QueuePacket(0xc000226600, 0x0, 0x0, 0x2, 0xc000855f50, 0x4, 0x5079, 0xc000855f4c, 0x4, 0xc002698800)
	pkg/tcpip/transport/tcp/protocol.go:137 +0x9b fp=0xc08368a0a8 sp=0xc08368a038 pc=0xad765b
gvisor.dev/gvisor/pkg/tcpip/stack.(*endpointsByNIC).handlePacket(0xc0024258f0, 0x2, 0xc000855f50, 0x4, 0x5079, 0xc000855f4c, 0x4, 0xc002698800, 0xc0035541b0)
	pkg/tcpip/stack/transport_demuxer.go:176 +0x20b fp=0xc08368a128 sp=0xc08368a0a8 pc=0x94b48b
gvisor.dev/gvisor/pkg/tcpip/stack.(*transportDemuxer).deliverPacket(0xc0000e4e40, 0xc000000006, 0xc002698800, 0x2, 0xc000855f50, 0x4, 0x5079, 0xc000855f4c, 0x4, 0xc000855f48)
	pkg/tcpip/stack/transport_demuxer.go:581 +0x430 fp=0xc08368a1c0 sp=0xc08368a128 pc=0x94de90
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).DeliverTransportPacket(0xc000e94000, 0x6, 0xc002698800, 0x0)
	pkg/tcpip/stack/nic.go:872 +0x2e5 fp=0xc08368a2c8 sp=0xc08368a1c0 pc=0x937f25
gvisor.dev/gvisor/pkg/tcpip/network/ipv4.(*endpoint).handleValidatedPacket(0xc000e96000, 0xc00268c9b6, 0x14, 0x3c, 0xc002698800, 0x126c52a, 0x2)
	pkg/tcpip/network/ipv4/ipv4.go:1047 +0x8ec fp=0xc08368aa90 sp=0xc08368a2c8 pc=0xaffc4c
gvisor.dev/gvisor/pkg/tcpip/network/ipv4.(*endpoint).HandlePacket(0xc000e96000, 0xc002698800)
	pkg/tcpip/network/ipv4/ipv4.go:836 +0x166 fp=0xc08368ad28 sp=0xc08368aa90 pc=0xafed66
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).DeliverNetworkPacket(0xc000e94000, 0xc000855f10, 0x6, 0xc000855f16, 0x6, 0xc000000800, 0xc002698800)
	pkg/tcpip/stack/nic.go:779 +0x2b0 fp=0xc08368add0 sp=0xc08368ad28 pc=0x9378f0
gvisor.dev/gvisor/pkg/tcpip/link/nested.(*Endpoint).DeliverNetworkPacket(0xc000848540, 0xc000855f10, 0x6, 0xc000855f16, 0x6, 0x800, 0xc002698800)
	pkg/tcpip/link/nested/nested.go:59 +0xbe fp=0xc08368ae28 sp=0xc08368add0 pc=0xba349e
gvisor.dev/gvisor/pkg/tcpip/link/sniffer.(*endpoint).DeliverNetworkPacket(0xc000848540, 0xc000855f10, 0x6, 0xc000855f16, 0x6, 0xc000000800, 0xc002698800)
	pkg/tcpip/link/sniffer/sniffer.go:140 +0x94 fp=0xc08368ae70 sp=0xc08368ae28 pc=0xba41f4
gvisor.dev/gvisor/pkg/tcpip/link/nested.(*Endpoint).DeliverNetworkPacket(0xc000b30730, 0xc000855f10, 0x6, 0xc000855f16, 0x6, 0x800, 0xc002698800)
	pkg/tcpip/link/nested/nested.go:59 +0xbe fp=0xc08368aec8 sp=0xc08368ae70 pc=0xba349e
gvisor.dev/gvisor/pkg/tcpip/link/ethernet.(*Endpoint).DeliverNetworkPacket(0xc000b30730, 0x0, 0x0, 0x0, 0x0, 0x800, 0xc002698800)
	pkg/tcpip/link/ethernet/ethernet.go:63 +0x15f fp=0xc08368af38 sp=0xc08368aec8 pc=0xe2b95f
gvisor.dev/gvisor/pkg/tcpip/link/loopback.(*endpoint).WriteRawPacket(0xc000912410, 0xc002698700, 0x0, 0x800)
	pkg/tcpip/link/loopback/loopback.go:107 +0xc8 fp=0xc08368af90 sp=0xc08368af38 pc=0xe2c508
gvisor.dev/gvisor/pkg/tcpip/link/loopback.(*endpoint).WritePacket(0xc000912410, 0xc000855ef0, 0x4, 0xc000855ef0, 0x4, 0x13bb678, 0x6, 0x0, 0x0, 0x100000800, ...)
	pkg/tcpip/link/loopback/loopback.go:80 +0x38 fp=0xc08368afc0 sp=0xc08368af90 pc=0xe2c358
gvisor.dev/gvisor/pkg/tcpip/link/nested.(*Endpoint).WritePacket(...)
	pkg/tcpip/link/nested/nested.go:107
gvisor.dev/gvisor/pkg/tcpip/link/ethernet.(*Endpoint).WritePacket(0xc000b30730, 0xc000855ef0, 0x4, 0xc000855ef0, 0x4, 0x13bb678, 0x6, 0x0, 0x0, 0x100000800, ...)
	pkg/tcpip/link/ethernet/ethernet.go:78 +0x139 fp=0xc08368b0a8 sp=0xc08368afc0 pc=0xe2bb79
gvisor.dev/gvisor/pkg/tcpip/link/nested.(*Endpoint).WritePacket(...)
	pkg/tcpip/link/nested/nested.go:107
gvisor.dev/gvisor/pkg/tcpip/link/sniffer.(*endpoint).WritePacket(0xc000848540, 0xc000855ef0, 0x4, 0xc000855ef0, 0x4, 0x13bb678, 0x6, 0x0, 0x0, 0x100000800, ...)
	pkg/tcpip/link/sniffer/sniffer.go:169 +0x10d fp=0xc08368b190 sp=0xc08368b0a8 pc=0xba44ed
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).writePacket(0xc000e94000, 0xc000855ef0, 0x4, 0xc000855ef0, 0x4, 0x13bb678, 0x6, 0x0, 0x0, 0x100000800, ...)
	pkg/tcpip/stack/nic.go:380 +0x12f fp=0xc08368b228 sp=0xc08368b190 pc=0x93586f
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).writePacketBuffer(0xc000e94000, 0xc000855ef0, 0x4, 0xc000855ef0, 0x4, 0x13bb678, 0x6, 0x0, 0x0, 0x100000800, ...)
	pkg/tcpip/stack/nic.go:324 +0xd0 fp=0xc08368b2d8 sp=0xc08368b228 pc=0x935170
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).enqueuePacketBuffer(0xc000e94000, 0xc002abc140, 0x800, 0x13d5740, 0xc002698700, 0xc00268c9ca, 0x28, 0x28)
	pkg/tcpip/stack/nic.go:339 +0x25d fp=0xc08368b428 sp=0xc08368b2d8 pc=0x9355bd
gvisor.dev/gvisor/pkg/tcpip/stack.(*nic).WritePacket(0xc000e94000, 0xc002abc140, 0xc000000800, 0xc002698700, 0x3c, 0x0)
	pkg/tcpip/stack/nic.go:317 +0x53 fp=0xc08368b478 sp=0xc08368b428 pc=0x935073
gvisor.dev/gvisor/pkg/tcpip/network/ipv4.(*endpoint).writePacket(0xc000e96000, 0xc002abc140, 0xc002698700, 0xc002abc100, 0x0, 0x0)
	pkg/tcpip/network/ipv4/ipv4.go:495 +0x375 fp=0xc08368b6b0 sp=0xc08368b478 pc=0xafccb5
gvisor.dev/gvisor/pkg/tcpip/network/ipv4.(*endpoint).WritePacket(0xc000e96000, 0xc002abc140, 0x2004000000006, 0xc002698700, 0xff800228, 0xc00268c9ca)
	pkg/tcpip/network/ipv4/ipv4.go:445 +0x179 fp=0xc08368b720 sp=0xc08368b6b0 pc=0xafc7d9
gvisor.dev/gvisor/pkg/tcpip/stack.(*Route).WritePacket(0xc002abc140, 0x4000000006, 0xc002698700, 0xc00017a7b8, 0x2)
	pkg/tcpip/stack/route.go:462 +0xad fp=0xc08368b760 sp=0xc08368b720 pc=0x93f28d
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.sendTCP(0xc002abc140, 0x5079, 0xc000855ef0, 0x4, 0x2, 0xc000855ef0, 0x4, 0x360f40a100020040, 0xff8000000000, 0xc000f850e0, ...)
	pkg/tcpip/transport/tcp/connect.go:890 +0x285 fp=0xc08368d5b0 sp=0xc08368b760 pc=0xac63a5
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*endpoint).sendTCP(0xc003002a00, 0xc002abc140, 0x5079, 0xc000855ef0, 0x4, 0x2, 0xc000855ef0, 0x4, 0x360f40a100020000, 0xff8000000000, ...)
	pkg/tcpip/transport/tcp/connect.go:782 +0xea fp=0xc08368d680 sp=0xc08368d5b0 pc=0xac576a
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*endpoint).sendSynTCP(0xc003002a00, 0xc002abc140, 0x5079, 0xc000855ef0, 0x4, 0x2, 0xc000855ef0, 0x4, 0x360f40a100020000, 0xff8000000000, ...)
	pkg/tcpip/transport/tcp/connect.go:773 +0xdc fp=0xc08368d760 sp=0xc08368d680 pc=0xac55bc
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*handshake).start(0xc003525380)
	pkg/tcpip/transport/tcp/connect.go:512 +0x2da fp=0xc08368d898 sp=0xc08368d760 pc=0xac43da
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*endpoint).connect(0xc003002a00, 0xc000000000, 0xc000855ef0, 0x4, 0x2, 0x101, 0x0, 0x0)
	pkg/tcpip/transport/tcp/endpoint.go:2363 +0x83a fp=0xc08368ef40 sp=0xc08368d898 pc=0xad157a
gvisor.dev/gvisor/pkg/tcpip/transport/tcp.(*endpoint).Connect(0xc003002a00, 0xc000000000, 0xc000855ef0, 0x4, 0xc000850002, 0x4, 0xc003550002)
	pkg/tcpip/transport/tcp/endpoint.go:2096 +0x7c fp=0xc08368f960 sp=0xc08368ef40 pc=0xad0c3c
gvisor.dev/gvisor/pkg/sentry/socket/netstack.(*socketOpsCommon).Connect(0xc000cf9730, 0xc002fd5500, 0xc000855ee0, 0x10, 0x10, 0x1, 0x0)
	pkg/sentry/socket/netstack/netstack.go:606 +0x364 fp=0xc08368fa60 sp=0xc08368f960 pc=0xb330a4
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.Connect(0xc002fd5500, 0x5, 0x200001c0, 0x10, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
	pkg/sentry/syscalls/linux/vfs2/socket.go:275 +0x1bb fp=0xc08368fb00 sp=0xc08368fa60 pc=0xe03ddb
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc002fd5500, 0x2a, 0x5, 0x200001c0, 0x10, 0x0, 0x0, 0x0, 0xe45930, 0x126b0a0, ...)
	pkg/sentry/kernel/task_syscall.go:103 +0x13c fp=0xc08368fc60 sp=0xc08368fb00 pc=0x9c513c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc002fd5500, 0x2a, 0x5, 0x200001c0, 0x10, 0x0, 0x0, 0x0, 0x0, 0x0)
	pkg/sentry/kernel/task_syscall.go:238 +0x66 fp=0xc08368fce8 sp=0xc08368fc60 pc=0x9c62c6
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc002fd5500, 0x2a, 0x5, 0x200001c0, 0x10, 0x0, 0x0, 0x0, 0x0, 0x0)
	pkg/sentry/kernel/task_syscall.go:198 +0x98 fp=0xc08368fd48 sp=0xc08368fce8 pc=0x9c5eb8
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc002fd5500, 0x2, 0xc002fd5500)
	pkg/sentry/kernel/task_syscall.go:173 +0x15c fp=0xc08368fe18 sp=0xc08368fd48 pc=0x9c585c
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc002fd5500, 0x13d45c0, 0x0)
	pkg/sentry/kernel/task_run.go:282 +0xc8c fp=0xc08368ff60 sp=0xc08368fe18 pc=0x9ba4ec
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc002fd5500, 0x5d4)
	pkg/sentry/kernel/task_run.go:97 +0x1af fp=0xc08368ffd0 sp=0xc08368ff60 pc=0x9b916f
runtime.goexit()
	src/runtime/asm_amd64.s:1371 +0x1 fp=0xc08368ffd8 sp=0xc08368ffd0 pc=0x472821
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:327 +0xfe