# HG changeset patch
# User gromero
# Date 1520901185 14400
#      Mon Mar 12 20:33:05 2018 -0400
# Node ID 34599b2378c5b94f774943488b20436db0ffe98b
# Parent  ecd91135d645bed6620abbd76ce30a906b6d7d44
8198794: Hotspot crash on Cassandra 3.11.1 startup with libnuma 2.0.3

diff --git a/src/hotspot/os/linux/os_linux.hpp b/src/hotspot/os/linux/os_linux.hpp
--- a/src/hotspot/os/linux/os_linux.hpp
+++ b/src/hotspot/os/linux/os_linux.hpp
@@ -258,8 +258,8 @@
   static void set_numa_bitmask_isbitset(numa_bitmask_isbitset_func_t func) { _numa_bitmask_isbitset = func; }
   static void set_numa_distance(numa_distance_func_t func) { _numa_distance = func; }
   static void set_numa_all_nodes(unsigned long* ptr) { _numa_all_nodes = ptr; }
-  static void set_numa_all_nodes_ptr(struct bitmask **ptr) { _numa_all_nodes_ptr = *ptr; }
-  static void set_numa_nodes_ptr(struct bitmask **ptr) { _numa_nodes_ptr = *ptr; }
+  static void set_numa_all_nodes_ptr(struct bitmask **ptr) { _numa_all_nodes_ptr = (ptr == NULL ? NULL : *ptr); }
+  static void set_numa_nodes_ptr(struct bitmask **ptr) { _numa_nodes_ptr = (ptr == NULL ? NULL : *ptr); }
   static int sched_getcpu_syscall(void);
  public:
   static int sched_getcpu()  { return _sched_getcpu != NULL ? _sched_getcpu() : -1; }
@@ -303,6 +303,18 @@
   static bool isnode_in_existing_nodes(unsigned int n) {
     if (_numa_bitmask_isbitset != NULL && _numa_nodes_ptr != NULL) {
       return _numa_bitmask_isbitset(_numa_nodes_ptr, n);
+    } else if (_numa_bitmask_isbitset != NULL && _numa_all_nodes_ptr != NULL) {
+      // Not all libnuma API v2 implement numa_nodes_ptr, so it's not possible
+      // to trust the API version for checking its absence. On the other hand,
+      // numa_nodes_ptr found in libnuma 2.0.9 and above is the only way to get
+      // a complete view of all numa nodes in the system, hence numa_nodes_ptr
+      // is used to handle CPU and nodes on architectures (like PowerPC) where
+      // it can exist nodes with CPUs but no memory or vice-versa and the nodes
+      // are besides that non-contiguous. For most of the architectures, like
+      // x86_64, numa_node_ptr presents the same node set as found in
+      // numa_all_nodes_ptr so it's possible to use numa_all_nodes_ptr as a
+      // substitute.
+      return _numa_bitmask_isbitset(_numa_all_nodes_ptr, n);
     } else
       return 0;
   }