diff --git a/compiler-rt/lib/dfsan/dfsan_interceptors.cpp b/compiler-rt/lib/dfsan/dfsan_interceptors.cpp
--- a/compiler-rt/lib/dfsan/dfsan_interceptors.cpp
+++ b/compiler-rt/lib/dfsan/dfsan_interceptors.cpp
@@ -22,6 +22,18 @@
 
 static bool interceptors_initialized;
 
+namespace {
+
+void ReleaseShadowMemoryPagesToOS(void *addr, SIZE_T length) {
+  uptr beg_shadow_addr = (uptr)__dfsan::shadow_for(addr);
+  void *end_addr =
+      (void *)((uptr)addr + RoundUpTo(length, GetPageSizeCached()));
+  uptr end_shadow_addr = (uptr)__dfsan::shadow_for(end_addr);
+  ReleaseMemoryPagesToOS(beg_shadow_addr, end_shadow_addr);
+}
+
+}  // namespace
+
 INTERCEPTOR(void *, mmap, void *addr, SIZE_T length, int prot, int flags,
             int fd, OFF_T offset) {
   void *res;
@@ -34,7 +46,7 @@
     res = REAL(mmap)(addr, length, prot, flags, fd, offset);
 
   if (res != (void *)-1)
-    dfsan_set_label(0, res, RoundUpTo(length, GetPageSize()));
+    ReleaseShadowMemoryPagesToOS(res, length);
   return res;
 }
 
@@ -42,18 +54,14 @@
             int fd, OFF64_T offset) {
   void *res = REAL(mmap64)(addr, length, prot, flags, fd, offset);
   if (res != (void *)-1)
-    dfsan_set_label(0, res, RoundUpTo(length, GetPageSize()));
+    ReleaseShadowMemoryPagesToOS(res, length);
   return res;
 }
 
 INTERCEPTOR(int, munmap, void *addr, SIZE_T length) {
   int res = REAL(munmap)(addr, length);
   if (res != -1) {
-    uptr beg_shadow_addr = (uptr)__dfsan::shadow_for(addr);
-    void *end_addr =
-        (void *)((uptr)addr + RoundUpTo(length, GetPageSizeCached()));
-    uptr end_shadow_addr = (uptr)__dfsan::shadow_for(end_addr);
-    ReleaseMemoryPagesToOS(beg_shadow_addr, end_shadow_addr);
+    ReleaseShadowMemoryPagesToOS(addr, length);
   }
   return res;
 }
diff --git a/compiler-rt/test/dfsan/munmap_release_shadow.c b/compiler-rt/test/dfsan/release_shadow_space.c
rename from compiler-rt/test/dfsan/munmap_release_shadow.c
rename to compiler-rt/test/dfsan/release_shadow_space.c
--- a/compiler-rt/test/dfsan/munmap_release_shadow.c
+++ b/compiler-rt/test/dfsan/release_shadow_space.c
@@ -23,11 +23,14 @@
 
   char *p = mmap(NULL, map_size, PROT_READ | PROT_WRITE,
                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  memset(p, 0xff, map_size);
+  size_t after_mmap = get_rss_kb();
+
   const dfsan_label label = dfsan_create_label("l", 0);
   char val = 0xff;
   dfsan_set_label(label, &val, sizeof(val));
   memset(p, val, map_size);
-  size_t after_mmap = get_rss_kb();
+  size_t after_mmap_and_set_label = get_rss_kb();
 
   munmap(p, map_size);
   size_t after_munmap = get_rss_kb();
@@ -36,19 +39,25 @@
                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   dfsan_set_label(label, &val, sizeof(val));
   memset(p, val, map_size);
-  size_t after_mmap2 = get_rss_kb();
+  size_t after_mmap_and_set_label2 = get_rss_kb();
 
-  fprintf(stderr, "RSS at start: %td, after mmap: %td, after mumap: %td, after mmap2: %td\n",
-          before, after_mmap, after_munmap, after_mmap2);
+  fprintf(
+      stderr,
+      "RSS at start: %td, after mmap: %td, after mmap+set label: %td, after "
+      "mumap: %td, after another mmap+set label: %td\n",
+      before, after_mmap, after_mmap_and_set_label, after_munmap,
+      after_mmap_and_set_label2);
 
   // The memory after mmap increases 3 times of map_size because the overhead of
   // shadow memory is 2x.
-  const size_t mmap_cost_kb = 3 * (map_size >> 10);
+  const size_t mmap_cost_kb = map_size >> 10;
+  const size_t mmap_shadow_cost_kb = 2 * mmap_cost_kb;
   assert(after_mmap >= before + mmap_cost_kb);
-  // OS does not release memory to the same level as the start of the program.
-  // The assert checks the memory after munmap up to a delta.
+  assert(after_mmap_and_set_label >= after_mmap + mmap_shadow_cost_kb);
+  // OS does not release memory after munmap to the same level as the start of
+  // the program. The assert checks the memory after another mmap up to a delta.
   const size_t delta = 50000;
-  assert(after_mmap2 <= after_mmap + delta);
+  assert(after_mmap_and_set_label2 <= after_mmap_and_set_label + delta);
 
   return 0;
 }