Merge branch 'issue-210-cray-hugepages' into 'master'

skip instrumentation attempts on anonymous mmap()

Closes #210

See merge request !5

ChangeLog

@@ -7,6 +7,9 @@ Darshan-3.1.3-pre1
 * add --enable-HDF5_1.10 configure option to explicitly enable HDF5 1.10+
   support, needed on some platforms for API compatibility 
   - contributed by Karl-Ulrich Bamberg
+* skip instrumentation attempts for anonymous mmap() calls; this avoids a
+  potentential deadlock condition when used with hugepages on Cray systems.
+  Reported by Glenn Lockwood and Cristian Simarro.
 
 Darshan-3.1.2
 =============

darshan-runtime/lib/darshan-posix.c

@@ -925,6 +925,14 @@ void* DARSHAN_DECL(mmap)(void *addr, size_t length, int prot, int flags,
 
     MAP_OR_FAIL(mmap);
 
+    if(fd < 0 || (flags & MAP_ANONYMOUS))
+    {
+        /* mmap is not associated with a backing file; skip all Darshan
+         * characterization attempts.
+         */
+        return(__real_mmap(addr, length, prot, flags, fd, offset));
+    }
+
     ret = __real_mmap(addr, length, prot, flags, fd, offset);
     if(ret == MAP_FAILED)
         return(ret);
@@ -948,6 +956,14 @@ void* DARSHAN_DECL(mmap64)(void *addr, size_t length, int prot, int flags,
 
     MAP_OR_FAIL(mmap64);
 
+    if(fd < 0 || (flags & MAP_ANONYMOUS))
+    {
+        /* mmap is not associated with a backing file; skip all Darshan
+         * characterization attempts.
+         */
+        return(__real_mmap64(addr, length, prot, flags, fd, offset));
+    }
+
     ret = __real_mmap64(addr, length, prot, flags, fd, offset);
     if(ret == MAP_FAILED)
         return(ret);