Fix off-by-one bug in LWLockRegisterTranche().

Original coding failed to enlarge the array as required if
the requested tranche_id was equal to LWLockTranchesAllocated.

In passing, fix poor style of not casting the result of (re)palloc.

diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 36b4b8bbeaab5ad0501167a6ee4b8939e5e0f121..df8f9bfd893f34fa3a0a1dd8d90521db339c24cd 100644 (file)
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -350,8 +350,9 @@ CreateLWLocks(void)
        if (LWLockTrancheArray == NULL)
        {
                LWLockTranchesAllocated = 16;
-               LWLockTrancheArray = MemoryContextAlloc(TopMemoryContext,
-                       LWLockTranchesAllocated * sizeof(LWLockTranche *));
+               LWLockTrancheArray = (LWLockTranche **)
+                       MemoryContextAlloc(TopMemoryContext,
+                                                          LWLockTranchesAllocated * sizeof(LWLockTranche *));
        }
 
        MainLWLockTranche.name = "main";
@@ -423,11 +424,12 @@ LWLockRegisterTranche(int tranche_id, LWLockTranche *tranche)
        {
                int             i = LWLockTranchesAllocated;
 
-               while (i < tranche_id)
+               while (i <= tranche_id)
                        i *= 2;
 
-               LWLockTrancheArray = repalloc(LWLockTrancheArray,
-                                                                         i * sizeof(LWLockTranche *));
+               LWLockTrancheArray = (LWLockTranche **)
+                       repalloc(LWLockTrancheArray,
+                                        i * sizeof(LWLockTranche *));
                LWLockTranchesAllocated = i;
        }