BUG#10948 NDB Replication: Race condition with ALTER/DROP table

BUG#9826  Server crash on schema change ("drop table", "alter table") with NDB

See note on 10948 for detailed explanation.

struct a { void* a; long long b[1]; };

on PPC32 (and 32bit pa risc): 16
on x86: 12

so a malloc(sizeof(void*)+extra_bits) is wrong.

Assuming that the long long is 64 bit aligned as non-aligned 64bit accesses
are rather expensive on ppc.

Thanks to paulus for doing the PPC port of valgrind.
Without which I would no doubt still be trying to find this.


ndb/src/ndbapi/DictCache.cpp:
  Fix allocation size for Ndb_local_table_info for architectures such as PPC and PA-RISC (32bit)
  where
  struct a { void* a; long long b;};
  is 64 bit aligned (i.e. sizeof(struct a)==16)
ndb/src/ndbapi/DictCache.hpp:
  Add warning about having to be the last member in the structure

2 files changed, 3 insertions, 2 deletions

diff --git a/ndb/src/ndbapi/DictCache.cpp b/ndb/src/ndbapi/DictCache.cpp
index 9cdd68272ad..ccc45a04824 100644
--- a/ndb/src/ndbapi/DictCache.cpp
+++ b/ndb/src/ndbapi/DictCache.cpp
@@ -24,7 +24,8 @@
 Ndb_local_table_info *
 Ndb_local_table_info::create(NdbTableImpl *table_impl, Uint32 sz)
 {
-  Uint32 tot_size= sizeof(NdbTableImpl *) + ((sz+7)>>3)<<3; // round to Uint64
+  Uint32 tot_size= sizeof(Ndb_local_table_info) - sizeof(Uint64)
+    + ((sz+7) & ~7); // round to Uint64
   void *data= malloc(tot_size);
   if (data == 0)
     return 0;
diff --git a/ndb/src/ndbapi/DictCache.hpp b/ndb/src/ndbapi/DictCache.hpp
index 58c08a93e61..ca31c345396 100644
--- a/ndb/src/ndbapi/DictCache.hpp
+++ b/ndb/src/ndbapi/DictCache.hpp
@@ -33,7 +33,7 @@ public:
   static Ndb_local_table_info *create(NdbTableImpl *table_impl, Uint32 sz=0);
   static void destroy(Ndb_local_table_info *);
   NdbTableImpl *m_table_impl;
-  Uint64 m_local_data[1];
+  Uint64 m_local_data[1]; // Must be last member. Used to access extra space.
 private:
   Ndb_local_table_info(NdbTableImpl *table_impl);
   ~Ndb_local_table_info();