You can play h6.
Fianchetto kingside is uneasy for me.
When it's obvious an attack is coming on one flank, I think of it as a necessity to counter-attack on the other flank.
I favor c6 in this position, follwed at some point by b5, and possibly Qa5. I may castle first, though, because my king will be relatively safe, and castling will only encourage a continued and focused attack by my opponent toward that flank.
My well defended king will make an attractive target, but not a particularly vulnerable one. My opponent's queenside, while it doesn't yet have an obvious target, will be less well organized for defense.
Think of it as white sending his elite troops against your fortress, while your ramshackle brigade of outlaws and brigands sneaks off in the night to pillage his poorly defended farms and trading posts.
There's more than one way to win a war.

On the other hand, the best way to counter an offense on the flank is by counterattack in the center!

You can always played Re8 after you've castled ... that way, if White play Bh6 you can play Bh8, preserving your DSB.

Really thank you for great answers everybody.
All of them helps me.
Especially Fiveofswords-san, I didn't know that this is a kind of which is called 150 attack, I'll look into this attack from now.
But until I get concrete solution in my mind, I play more classical defence as you say.
As the other answers say, I'm not good at steady pawn advance or attack,
I guess I have to get some book about this.
Thank you everybody!
Fianchetting kingside and making a house for King is
very usual play, I think. In fact I sometimes do this.
But I sometimes get troubled with a position like this.
The move order is (for example),
1.d4 Nf6 2.e4 d6 3.Nc3 g6 4.Be3 Bg7 5.Qd2
What makes me(black) uncofortable is c1-h6 diagonal,
Bh6 of white is terrifying for me.
Sometimes this position happens (at least in my games).
Therefore recently I don't like fianchetto.
When I first met this position I played ...h5 because
my Rook also covers h6 square. However computer analysis says
this is not good.
Well, how should I think of this position ?
Options which come up in my head now are below.
1. This position is not good for black and allowing white this position itself is ever stupid. I should have started some attack before this position !
2. Actually this postion is not danger at all. I'm just a natural-born worrier HAHAHA !
3. This needs me some attention, but not so critical. Continue usual developing moves !
Well,,, I need your advice.
Thank you for your time.