mod p modular forms

Question

It is known due to Deligne that the space of modular forms over a field of char. $3$ is $k[b_2, \Delta]$ where $b_2$ is a modular form of weight 2. In particular, $b_2$ gives an element in $H^0 (M_{1, 1, k}, \Omega^{1})$. My question is: does it extend to $\bar{M}_{1, 1, k}$? That is, does this form extend to the cusp point or does it have a pole at the cusp point?