diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/conformer.py b/egs/librispeech/ASR/pruned_transducer_stateless7/conformer.py
index 34b9d00f0..f90bb9379 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/conformer.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/conformer.py
@@ -269,7 +269,11 @@ class ConformerEncoderLayer(nn.Module):
         src = src + self.dropout(src_att)
 
         # convolution module
-        src = src + self.dropout(self.conv_module(src))
+        src = src + self.dropout(
+            self.conv_module(src, src_key_padding_mask=src_key_padding_mask)
+        )
+
+
 
         # feed forward module
         src = src + self.dropout(self.feed_forward(src))
@@ -925,11 +929,16 @@ class ConvolutionModule(nn.Module):
             initial_scale=0.5,
         )
 
-    def forward(self, x: Tensor) -> Tensor:
+    def forward(self,
+                x: Tensor,
+                src_key_padding_mask: Optional[Tensor] = None,
+    ) -> Tensor:
         """Compute convolution module.
 
         Args:
             x: Input tensor (#time, batch, channels).
+           src_key_padding_mask: the mask for the src keys per batch (optional):
+               (batch, #time), contains bool in masked positions.
 
         Returns:
             Tensor: Output tensor (#time, batch, channels).
@@ -944,6 +953,9 @@ class ConvolutionModule(nn.Module):
         x = self.deriv_balancer1(x)
         x = nn.functional.glu(x, dim=1)  # (batch, channels, time)
 
+        if src_key_padding_mask is not None:
+            x.masked_fill_(src_key_padding_mask.unsqueeze(1).expand_as(x), 0.0)
+
         # 1D Depthwise Conv
         x = self.depthwise_conv(x)