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

[Andrey Churbanov via Phabricator via Openmp-commits]

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.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D112174

Files:
  openmp/runtime/src/ompt-general.cpp


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_CONTINUED_PRINT("Success. \n");
         OMPT_VERBOSE_INIT_PRINT("Searching for ompt_start_tool in %s... ",
                                 fname);
+        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
 #elif KMP_OS_WINDOWS
       OMPT_VERBOSE_INIT_PRINT("Opening %s... ", fname);


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