[Openmp-commits] [PATCH] D112174: [OpenMP] Fix possible NULL dereference

Andrey Churbanov via Phabricator via Openmp-commits openmp-commits at lists.llvm.org
Wed Oct 20 13:00:12 PDT 2021

AndreyChurbanov created this revision.
AndreyChurbanov added reviewers: hbae, jlpeyton, Nawrin, tlwilmar.
AndreyChurbanov added a project: OpenMP.
Herald added subscribers: guansong, yaxunl.
AndreyChurbanov requested review of this revision.
Herald added a reviewer: jdoerfert.
Herald added subscribers: openmp-commits, sstefan1.

According to dlsym description, the value of symbol could be NULL,
and there is no error in this case. Thus dlerror will also return NULL in
this case. We need to check the value returned by dlerror before printing it.

  rG LLVM Github Monorepo



Index: openmp/runtime/src/ompt-general.cpp
--- openmp/runtime/src/ompt-general.cpp
+++ openmp/runtime/src/ompt-general.cpp
@@ -346,9 +346,16 @@
         OMPT_VERBOSE_INIT_PRINT("Searching for ompt_start_tool in %s... ",
+        dlerror(); // Clear any existing error
         start_tool = (ompt_start_tool_t)dlsym(h, "ompt_start_tool");
         if (!start_tool) {
-          OMPT_VERBOSE_INIT_CONTINUED_PRINT("Failed: %s\n", dlerror());
+          char *error = dlerror();
+          if (error != NULL) {
+            OMPT_VERBOSE_INIT_CONTINUED_PRINT("Failed: %s\n", error);
+          } else {
+            OMPT_VERBOSE_INIT_CONTINUED_PRINT("Failed: %s\n",
+                                              "ompt_start_tool = NULL");
+          }
         } else
       OMPT_VERBOSE_INIT_PRINT("Opening %s... ", fname);

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