[BugFix] Fix EXAONE4 rotary embeddings (#23918)

Signed-off-by: lkm2835 <lkm2835@gmail.com>
Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

vllm/model_executor/models/exaone4.py

@@ -164,8 +164,8 @@ class Exaone4Attention(nn.Module):
         is_sliding = config.layer_types[layer_idx] == "sliding_attention"
         self.sliding_window = config.sliding_window if is_sliding else None
 
-        # apply rotary embeddings to every layer
-        self.apply_all_layers = not is_sliding
+        # apply rotary embeddings to every layer in full attention models
+        self.apply_rope_all_layers = "sliding_attention" not in config.layer_types
 
         self.rotary_emb = get_rope(
             self.head_dim,
@@ -201,7 +201,7 @@ class Exaone4Attention(nn.Module):
         k = self.k_norm(k)
         k = k.flatten(-2, -1)
 
-        if self.sliding_window or self.apply_all_layers:
+        if self.sliding_window or self.apply_rope_all_layers:
             q, k = self.rotary_emb(positions, q, k)
         attn_output = self.attn(q, k, v)
         output, _ = self.o_proj(attn_output)