diff --git a/racket/src/racket/gc2/block_cache.c b/racket/src/racket/gc2/block_cache.c
index 0f9ab8a729..f9f399a766 100644
--- a/racket/src/racket/gc2/block_cache.c
+++ b/racket/src/racket/gc2/block_cache.c
@@ -434,14 +434,19 @@ static void block_cache_protect_one_page(BlockCache* bc, void *p, size_t len, in
         GC_ASSERT(pos >= 0);
         GC_ASSERT(pos < (b->size >> LOG_APAGE_SIZE));
         GC_ASSERT(BD_MAP_GET_BIT(b->alloc_map, pos));
+        /* Since a queued mprotect affects more pages than the client can be sure of,
+           we have to accomodate redundant requests. */
         if (writeable) {
-          GC_ASSERT(BD_MAP_GET_BIT(b->protect_map, pos));
-          BD_MAP_UNSET_BIT(b->protect_map, pos);
+          if (BD_MAP_GET_BIT(b->protect_map, pos)) {
+            BD_MAP_UNSET_BIT(b->protect_map, pos);
+            os_protect_pages(p, len, writeable);
+          }
         } else {
-          GC_ASSERT(!BD_MAP_GET_BIT(b->protect_map, pos));
-          BD_MAP_SET_BIT(b->protect_map, pos);
+          if (!BD_MAP_GET_BIT(b->protect_map, pos)) {
+            BD_MAP_SET_BIT(b->protect_map, pos);
+            os_protect_pages(p, len, writeable);
+          }
         }
-        os_protect_pages(p, len, writeable);
       }
       break;
   default:
diff --git a/racket/src/racket/gc2/newgc.c b/racket/src/racket/gc2/newgc.c
index 42b0112352..8cc58863d1 100644
--- a/racket/src/racket/gc2/newgc.c
+++ b/racket/src/racket/gc2/newgc.c
@@ -4225,7 +4225,7 @@ static void mark_backpointers(NewGC *gc)
       GC_ASSERT(work->back_pointers);
 
       if (work->mprotected) {
-        /* expected only if QUEUED_MPROTECT_IS_PROMISCUOUS && AGE_GEN_0_TO_GEN_HALF(gc) */
+        /* expected only if QUEUED_MPROTECT_INFECTS_XXX && AGE_GEN_0_TO_GEN_HALF(gc) */
         work->mprotected = 0;
         mmu_write_unprotect_page(gc->mmu, work->addr, real_page_size(work), page_mmu_type(work), &work->mmu_src_block);
       }
@@ -4909,7 +4909,7 @@ static void protect_old_pages(NewGC *gc)
           if (!page->mprotected && !page->back_pointers) {
             page->mprotected = 1;
             mmu_queue_write_protect_range(mmu, page->addr, real_page_size(page), page_mmu_type(page), &page->mmu_src_block);
-          } else if (QUEUED_MPROTECT_IS_PROMISCUOUS)
+          } else if (QUEUED_MPROTECT_INFECTS_SMALL)
             page->mprotected = 1;
         }
       }
@@ -4921,7 +4921,7 @@ static void protect_old_pages(NewGC *gc)
       if (!page->mprotected && !page->back_pointers) {
         page->mprotected = 1;
         mmu_queue_write_protect_range(mmu, page->addr, APAGE_SIZE, page_mmu_type(page), &page->mmu_src_block);
-      } else if (QUEUED_MPROTECT_IS_PROMISCUOUS)
+      } else if (QUEUED_MPROTECT_INFECTS_MED)
         page->mprotected = 1;
     }
   }
diff --git a/racket/src/racket/gc2/vm.c b/racket/src/racket/gc2/vm.c
index 92d22f7e40..53795283ce 100644
--- a/racket/src/racket/gc2/vm.c
+++ b/racket/src/racket/gc2/vm.c
@@ -28,10 +28,11 @@ enum {
 
 #ifdef USE_BLOCK_CACHE
 # define USE_ALLOC_CACHE
-# define QUEUED_MPROTECT_IS_PROMISCUOUS 1
+# define QUEUED_MPROTECT_INFECTS_SMALL 1
 #else
-# define QUEUED_MPROTECT_IS_PROMISCUOUS 0
+# define QUEUED_MPROTECT_INFECTS_SMALL 0
 #endif
+#define QUEUED_MPROTECT_INFECTS_MED 0
 
 /* Either USE_ALLOC_CACHE or OS_ALLOCATOR_NEEDS_ALIGNMENT must be
    enabled, unless the lower-level allocator's alignment matches