diff --git a/probe_symbol.sh b/probe_symbol.sh
new file mode 100644
index 00000000..1c2df001
--- /dev/null
+++ b/probe_symbol.sh
@@ -0,0 +1,73 @@
+#!/bin/bash
+# probe_symbol.sh — Find which .so has silu_and_mul
+echo "=== Searching for silu_and_mul symbol ==="
+
+# The mangled name from the error
+SYMBOL="_ZN8ixformer5infer12silu_and_mulERN2at6TensorES3_"
+
+echo ""
+echo "--- ixformer package .so files ---"
+for f in /usr/local/corex/lib64/python3/dist-packages/ixformer/*.so; do
+    echo -n "  $f: "
+    if nm -D "$f" 2>/dev/null | grep -q "$SYMBOL"; then
+        echo "FOUND ✓"
+    elif nm -D "$f" 2>/dev/null | grep -q "silu_and_mul"; then
+        echo "has silu_and_mul (different mangling):"
+        nm -D "$f" 2>/dev/null | grep "silu_and_mul"
+    else
+        echo "not found"
+    fi
+done
+
+echo ""
+echo "--- /usr/local/corex/lib64/*.so ---"
+for f in /usr/local/corex/lib64/*.so*; do
+    r=$(nm -D "$f" 2>/dev/null | grep -c "silu_and_mul")
+    if [ "$r" -gt 0 ]; then
+        echo "  $f: $r matches"
+        nm -D "$f" 2>/dev/null | grep "silu_and_mul" | head -3
+    fi
+done
+
+echo ""
+echo "--- Global search (may take a moment) ---"
+find /usr/local/corex -name "*.so*" 2>/dev/null | while read f; do
+    r=$(nm -D "$f" 2>/dev/null | grep -c "silu_and_mul")
+    if [ "$r" -gt 0 ]; then
+        echo "  $f: $r matches"
+        nm -D "$f" 2>/dev/null | grep "silu_and_mul" | head -3
+    fi
+done
+
+echo ""
+echo "--- Also check vllm/torch installed .so ---"
+find /usr/local/corex/lib64/python3/dist-packages/vllm -name "*.so" 2>/dev/null | while read f; do
+    r=$(nm -D "$f" 2>/dev/null | grep -c "silu_and_mul")
+    if [ "$r" -gt 0 ]; then
+        echo "  $f: $r matches"
+        nm -D "$f" 2>/dev/null | grep "silu_and_mul" | head -3
+    fi
+done
+
+echo ""
+echo "--- Python check: how does ixformer.functions.silu_and_mul resolve? ---"
+python3 -c "
+import ixformer.functions as F
+fn = F.silu_and_mul
+print(f'Type: {type(fn)}')
+print(f'Module: {getattr(fn, \"__module__\", \"?\")}')
+# Check if it's from a torch op or C++ binding
+import inspect
+try:
+    print(f'File: {inspect.getfile(fn)}')
+except:
+    print('File: built-in/C extension')
+# Try to find the actual implementation
+import ixformer
+print(f'ixformer._C: {hasattr(ixformer, \"_C\")}')
+if hasattr(ixformer, '_C'):
+    c = ixformer._C
+    for attr in dir(c):
+        if 'silu' in attr.lower():
+            print(f'  _C.{attr}')
+"