--- old/src/os/linux/vm/os_linux.cpp	Fri Jun 21 13:43:58 2013
+++ new/src/os/linux/vm/os_linux.cpp	Fri Jun 21 13:43:57 2013
@@ -1682,12 +1682,13 @@
   Dl_info dlinfo;
 
   if (libjvm_base_addr == NULL) {
-    dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
-    libjvm_base_addr = (address)dlinfo.dli_fbase;
+    if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
+      libjvm_base_addr = (address)dlinfo.dli_fbase;
+    }
     assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
   }
 
-  if (dladdr((void *)addr, &dlinfo)) {
+  if (dladdr((void *)addr, &dlinfo) != 0) {
     if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
   }
 
@@ -1696,24 +1697,30 @@
 
 bool os::dll_address_to_function_name(address addr, char *buf,
                                       int buflen, int *offset) {
+  // buf is not optional, but offset is optional
+  assert(buf != NULL, "sanity check");
+
   Dl_info dlinfo;
 
-  if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
-    if (buf != NULL) {
-      if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
+  if (dladdr((void*)addr, &dlinfo) != 0) {
+    // see if we have a matching symbol
+    if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
+      if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
         jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
       }
+      if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
+      return true;
     }
-    if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
-    return true;
-  } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
-    if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
-        buf, buflen, offset, dlinfo.dli_fname)) {
-       return true;
+    // no matching symbol so try for just file info
+    if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
+      if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
+                          buf, buflen, offset, dlinfo.dli_fname)) {
+        return true;
+      }
     }
   }
 
-  if (buf != NULL) buf[0] = '\0';
+  buf[0] = '\0';
   if (offset != NULL) *offset = -1;
   return false;
 }
@@ -1764,6 +1771,9 @@
 
 bool os::dll_address_to_library_name(address addr, char* buf,
                                      int buflen, int* offset) {
+  // buf is not optional, but offset is optional
+  assert(buf != NULL, "sanity check");
+
   Dl_info dlinfo;
   struct _address_to_library_name data;
 
@@ -1782,12 +1792,16 @@
      // buf already contains library name
      if (offset) *offset = addr - data.base;
      return true;
-  } else if (dladdr((void*)addr, &dlinfo)){
-     if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
-     if (offset) *offset = addr - (address)dlinfo.dli_fbase;
+  } else if (dladdr((void*)addr, &dlinfo) != 0) {
+     if (dlinfo.dli_fname != NULL) {
+       jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
+     }
+     if (dlinfo.dli_fbase != NULL && offset != NULL) {
+       *offset = addr - (address)dlinfo.dli_fbase;
+     }
      return true;
   } else {
-     if (buf) buf[0] = '\0';
+     buf[0] = '\0';
      if (offset) *offset = -1;
      return false;
   }
@@ -2317,8 +2331,11 @@
   bool ret = dll_address_to_library_name(
                 CAST_FROM_FN_PTR(address, os::jvm_path),
                 dli_fname, sizeof(dli_fname), NULL);
-  assert(ret != 0, "cannot locate libjvm");
-  char *rp = realpath(dli_fname, buf);
+  assert(ret, "cannot locate libjvm");
+  char *rp = NULL;
+  if (ret && dli_fname[0] != '\0') {
+    rp = realpath(dli_fname, buf);
+  }
   if (rp == NULL)
     return;
 
@@ -4730,20 +4747,20 @@
 bool os::find(address addr, outputStream* st) {
   Dl_info dlinfo;
   memset(&dlinfo, 0, sizeof(dlinfo));
-  if (dladdr(addr, &dlinfo)) {
+  if (dladdr(addr, &dlinfo) != 0) {
     st->print(PTR_FORMAT ": ", addr);
-    if (dlinfo.dli_sname != NULL) {
+    if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
       st->print("%s+%#x", dlinfo.dli_sname,
                  addr - (intptr_t)dlinfo.dli_saddr);
-    } else if (dlinfo.dli_fname) {
+    } else if (dlinfo.dli_fbase != NULL) {
       st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
     } else {
       st->print("<absolute address>");
     }
-    if (dlinfo.dli_fname) {
+    if (dlinfo.dli_fname != NULL) {
       st->print(" in %s", dlinfo.dli_fname);
     }
-    if (dlinfo.dli_fbase) {
+    if (dlinfo.dli_fbase != NULL) {
       st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
     }
     st->cr();
@@ -4756,7 +4773,7 @@
       if (!lowest)  lowest = (address) dlinfo.dli_fbase;
       if (begin < lowest)  begin = lowest;
       Dl_info dlinfo2;
-      if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
+      if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
           && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
         end = (address) dlinfo2.dli_saddr;
       Disassembler::decode(begin, end, st);