Adjust fix_alloc sizes to guarantee they fit a dd block

This failed on 32-bit builds, and wasn't noticed because 32-bit
debug builds didn't run during the test period.

2 files changed, 12 insertions, 6 deletions

diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index 493c3799c2..166d5c48a5 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -568,7 +568,10 @@ static void adjust_fix_alloc_sizes(UWord extra_block_size)
 	    for (i=0; i < tspec->size; i++) {
 		Allctr_t* allctr = tspec->allctr[i];
 		for (j=0; j < ERTS_ALC_NO_FIXED_SIZES; ++j) {
-		    allctr->fix[j].type_size += extra_block_size;
+                    size_t size = allctr->fix[j].type_size;
+                    size = MAX(size + extra_block_size,
+                               sizeof(ErtsAllctrDDBlock_t));
+		    allctr->fix[j].type_size = size;
 		}
 	    }
 	}
@@ -576,8 +579,11 @@ static void adjust_fix_alloc_sizes(UWord extra_block_size)
 	{
 	    Allctr_t* allctr = erts_allctrs_info[ERTS_ALC_A_FIXED_SIZE].extra;
 	    for (j=0; j < ERTS_ALC_NO_FIXED_SIZES; ++j) {
-		allctr->fix[j].type_size += extra_block_size;
-	    }	
+                size_t size = allctr->fix[j].type_size;
+                size = MAX(size + extra_block_size,
+                           sizeof(ErtsAllctrDDBlock_t));
+                allctr->fix[j].type_size = size;
+	    }
 	}
     }
 }
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c
index 1c95385649..77f52a5fe6 100644
--- a/erts/emulator/beam/erl_alloc_util.c
+++ b/erts/emulator/beam/erl_alloc_util.c
@@ -1395,8 +1395,8 @@ fix_cpool_alloc(Allctr_t *allctr, ErtsAlcType_t type, Uint size)
     ErtsAlcFixList_t *fix;
 
     fix = &allctr->fix[ERTS_ALC_FIX_TYPE_IX(type)];
-    ASSERT(type == fix->type);
-    ASSERT(size == fix->type_size);
+    ASSERT(type == fix->type && size == fix->type_size);
+    ASSERT(size >= sizeof(ErtsAllctrDDBlock_t));
 
     res = fix->list;
     if (res) {
@@ -1539,6 +1539,7 @@ fix_nocpool_alloc(Allctr_t *allctr, ErtsAlcType_t type, Uint size)
 
     fix = &allctr->fix[ERTS_ALC_FIX_TYPE_IX(type)];
     ASSERT(type == fix->type && size == fix->type_size);
+    ASSERT(size >= sizeof(ErtsAllctrDDBlock_t));
 
     ERTS_DBG_CHK_FIX_LIST(allctr, fix, ix, 1);
     fix->u.nocpool.used++;
@@ -6617,7 +6618,6 @@ erts_alcu_start(Allctr_t *allctr, AllctrInit_t *init)
 	    allctr->fix[i].type = ERTS_ALC_N2T(i + ERTS_ALC_N_MIN_A_FIXED_SIZE);
 	    allctr->fix[i].list_size = 0;
 	    allctr->fix[i].list = NULL;
-	    ASSERT(allctr->fix[i].type_size >= sizeof(ErtsAllctrDDBlock_t));
 	    if (ERTS_ALC_IS_CPOOL_ENABLED(allctr)) {
 		allctr->fix[i].u.cpool.min_list_size = 0;
 		allctr->fix[i].u.cpool.shrink_list = 0;