wgengine/netstack: disable gVisor GSO on Linux (#13213)

net/tstun.Wrapper.InjectInboundPacketBuffer is not GSO-aware, which can
break quad-100 TCP streams as a result. Linux is the only platform where
gVisor GSO was previously enabled.

Updates tailscale/corp#22511
Updates #13211

Signed-off-by: Jordan Whited <jordan@tailscale.com>

wgengine/netstack/netstack.go

@@ -329,7 +329,8 @@ func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magi
 		// TODO(jwhited): add Windows GSO support https://github.com/tailscale/corp/issues/21874
 		// TODO(jwhited): exercise enableGRO in relation to https://github.com/tailscale/corp/issues/22353
 		linkEP = newLinkEndpoint(512, uint32(tstun.DefaultTUNMTU()), "", disableGRO)
-		linkEP.SupportedGSOKind = stack.HostGSOSupported
+		// TODO(jwhited): re-enable GSO https://github.com/tailscale/corp/issues/22511
+		linkEP.SupportedGSOKind = stack.GSONotSupported
 	} else {
 		linkEP = newLinkEndpoint(512, uint32(tstun.DefaultTUNMTU()), "", disableGRO)
 	}