Bug 844513: PL_ARENA_ALLOCATE should not let PL_ArenaAllocate unpoisonNSPR_4_10_BETA2

the alignment gap. Use an unsigned char* typecast for pointer arithmetic.
r=matspal,choller.

3 files changed, 5 insertions, 5 deletions

diff --git a/lib/ds/plarena.c b/lib/ds/plarena.c
index 211dd671..23610ea8 100644
--- a/lib/ds/plarena.c
+++ b/lib/ds/plarena.c
@@ -157,7 +157,6 @@ PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
                 pool->current = a;
                 rp = (char *)a->avail;
                 a->avail += nb;
-                PL_MAKE_MEM_UNDEFINED(rp, nb);
                 return rp;
             }
         } while( NULL != (a = a->next) );
@@ -188,7 +187,6 @@ PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
                 pool->current = a;
                 if ( NULL == pool->first.next )
                     pool->first.next = a;
-                PL_MAKE_MEM_UNDEFINED(rp, nb);
                 return(rp);
             }
         }
@@ -215,7 +213,6 @@ PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
                 pool->first.next = a;
             PL_COUNT_ARENA(pool,++);
             COUNT(pool, nmallocs);
-            PL_MAKE_MEM_UNDEFINED(rp, nb);
             return(rp);
         }
     }
diff --git a/lib/ds/plarena.h b/lib/ds/plarena.h
index c4974304..8dcfb3e5 100644
--- a/lib/ds/plarena.h
+++ b/lib/ds/plarena.h
@@ -143,10 +143,10 @@ void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
         if (_q > _a->limit) { \
             _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
         } else { \
-            PL_MAKE_MEM_UNDEFINED((void *)_p, nb); \
             _a->avail = _q; \
         } \
         p = (void *)_p; \
+        PL_MAKE_MEM_UNDEFINED(p, nb); \
         PL_ArenaCountAllocation(pool, nb); \
     PR_END_MACRO
 
@@ -158,7 +158,7 @@ void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
         PRUword _q = _p + _incr; \
         if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
             _q <= _a->limit) { \
-            PL_MAKE_MEM_UNDEFINED((void *)((PRUword)(p) + size), incr); \
+            PL_MAKE_MEM_UNDEFINED((unsigned char *)(p) + size, incr); \
             _a->avail = _q; \
             PL_ArenaCountInplaceGrowth(pool, size, incr); \
         } else { \
diff --git a/lib/ds/plarenas.h b/lib/ds/plarenas.h
index f4a00cd1..98bd7f87 100644
--- a/lib/ds/plarenas.h
+++ b/lib/ds/plarenas.h
@@ -47,6 +47,9 @@ PR_EXTERN(void) PL_CompactArenaPool(PLArenaPool *pool);
 
 /*
 ** Friend functions used by the PL_ARENA_*() macros.
+**
+** WARNING: do not call these functions directly. Always use the
+** PL_ARENA_*() macros.
 **/
 PR_EXTERN(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb);