diff --git a/llvm/lib/Target/BPF/BTFDebug.cpp b/llvm/lib/Target/BPF/BTFDebug.cpp
--- a/llvm/lib/Target/BPF/BTFDebug.cpp
+++ b/llvm/lib/Target/BPF/BTFDebug.cpp
@@ -1343,6 +1343,8 @@
     // been generated, construct one based on function signature.
     if (LineInfoGenerated == false) {
       auto *S = MI->getMF()->getFunction().getSubprogram();
+      if (!S) // unable to get subprogram
+        return;
       MCSymbol *FuncLabel = Asm->getFunctionBegin();
       constructLineInfo(S, FuncLabel, S->getLine(), 0);
       LineInfoGenerated = true;