[Openmp-commits] [openmp] [OpenMP] Fix use of uninitialized Dl_info when dladdr fails in ompd_init (PR #193643)

[Mark Zhuang via Openmp-commits]

https://github.com/zqb-all created https://github.com/llvm/llvm-project/pull/193643

When dladdr() fails, dl_info is left uninitialized. The code printed the error but then fell through to unconditionally call strrchr(dl_info.dli_fname, '/'), accessing an uninitialized pointer -- typically NULL on the stack -- causing a SIGSEGV.

Fix by turning the second 'if' into 'else if', so the path-extraction block is only reached when dladdr() succeeded and dl_info is valid.

Assisted-by: Claude Sonnet 4.6

>From 63e7f6ab75d6154a9033eae6b0b6b53066a2d47c Mon Sep 17 00:00:00 2001
From: Mark Zhuang <mark.zhuang at spacemit.com>
Date: Thu, 23 Apr 2026 09:10:33 +0800
Subject: [PATCH] [OpenMP] Fix use of uninitialized Dl_info when dladdr fails
 in ompd_init

When dladdr() fails, dl_info is left uninitialized.
The code printed the error but then fell through to unconditionally
call strrchr(dl_info.dli_fname, '/'), accessing an uninitialized
pointer -- typically NULL on the stack -- causing a SIGSEGV.

Fix by turning the second 'if' into 'else if', so the path-extraction
block is only reached when dladdr() succeeded and dl_info is valid.

Assisted-by: Claude Sonnet 4.6
---
 openmp/runtime/src/ompd-specific.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/openmp/runtime/src/ompd-specific.cpp b/openmp/runtime/src/ompd-specific.cpp
index c4018789eb5b2..b0503f1d2ad1f 100644
--- a/openmp/runtime/src/ompd-specific.cpp
+++ b/openmp/runtime/src/ompd-specific.cpp
@@ -88,10 +88,9 @@ void ompd_init() {
   int ret = dladdr((void *)ompd_init, &dl_info);
   if (!ret) {
     fprintf(stderr, "%s\n", dlerror());
-  }
-  int lib_path_length;
-  if (strrchr(dl_info.dli_fname, '/')) {
-    lib_path_length = strrchr(dl_info.dli_fname, '/') - dl_info.dli_fname;
+  } else if (strrchr(dl_info.dli_fname, '/')) {
+    int lib_path_length =
+        strrchr(dl_info.dli_fname, '/') - dl_info.dli_fname;
     libname =
         (char *)malloc(lib_path_length + 12 /*for '/libompd.so' and '\0'*/);
     strncpy(libname, dl_info.dli_fname, lib_path_length);