diff --git a/compiler-rt/lib/scudo/standalone/linux.cpp b/compiler-rt/lib/scudo/standalone/linux.cpp
--- a/compiler-rt/lib/scudo/standalone/linux.cpp
+++ b/compiler-rt/lib/scudo/standalone/linux.cpp
@@ -20,6 +20,7 @@
 #include <fcntl.h>
 #include <linux/futex.h>
 #include <sched.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
@@ -116,6 +117,55 @@
   return NeedsMemset == Yes;
 }
 
+static uptr getProt(FILE *F, uptr Ptr, int *Prot) {
+  CHECK(F);
+  char line[1024];
+  u64 B, E;
+  do {
+    CHECK_NE(fgets(line, sizeof(line), F), nullptr);
+  } while (sscanf(line, "%llx-%llx ", &B, &E) != 2 || Ptr < B || Ptr >= E);
+
+  CHECK_LE(B, Ptr);
+  CHECK_LT(Ptr, E);
+
+  static const char Field[] = "VmFlags:";
+  do {
+    CHECK_NE(fgets(line, sizeof(line), F), nullptr);
+  } while (strncmp(line, Field, sizeof(Field) - 1) != 0);
+
+  *Prot = 0;
+  char *Saved = nullptr;
+  char *Token = strtok_r(line + sizeof(Field) - 1, " \n", &Saved);
+  for (; Token; Token = strtok_r(nullptr, " \n", &Saved)) {
+    if (strcmp(Token, "rd") == 0)
+      *Prot |= PROT_READ;
+    else if (strcmp(Token, "wr") == 0)
+      *Prot |= PROT_WRITE;
+    else if (strcmp(Token, "mt") == 0)
+      *Prot |= PROT_MTE;
+  }
+  return E;
+}
+
+static void releaseByReMap(void *Addr, uptr Size) {
+  FILE *F = fopen("/proc/self/smaps", "r");
+  while (Size) {
+    uptr B = reinterpret_cast<uptr>(Addr);
+    int Prot;
+    // FIXME: Tests do not catch if we just set PROT_READ | PROT_WRITE.
+    uptr E = getProt(F, B, &Prot);
+    uptr MapSize = Min(E - B, Size);
+    if (Addr != mmap(Addr, MapSize, Prot,
+                     MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
+                     -1, 0)) {
+      dieOnMapUnmapError();
+    }
+    Addr = reinterpret_cast<void *>(B + MapSize);
+    Size -= MapSize;
+  }
+  fclose(F);
+}
+
 void releasePagesToOS(uptr BaseAddress, uptr Offset, uptr Size,
                       UNUSED MapPlatformData *Data) {
   void *Addr = reinterpret_cast<void *>(BaseAddress + Offset);
@@ -123,7 +173,7 @@
     // Workaround for QEMU-user ignoring MADV_DONTNEED.
     // https://github.com/qemu/qemu/blob/b1cffefa1b163bce9aebc3416f562c1d3886eeaa/linux-user/syscall.c#L11941
     // https://bugs.launchpad.net/qemu/+bug/1926521
-    memset(Addr, 0, Size);
+    return releaseByReMap(Addr, Size);
   }
   while (madvise(Addr, Size, MADV_DONTNEED) == -1 && errno == EAGAIN) {
   }
diff --git a/compiler-rt/lib/scudo/standalone/tests/common_test.cpp b/compiler-rt/lib/scudo/standalone/tests/common_test.cpp
--- a/compiler-rt/lib/scudo/standalone/tests/common_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/common_test.cpp
@@ -47,9 +47,8 @@
   EXPECT_GT(getResidentMemorySize() - OnStart, Size - Threshold);
 
   releasePagesToOS((uptr)P, 0, Size, &Data);
+  EXPECT_LT(getResidentMemorySize() - OnStart, Threshold);
   EXPECT_EQ(std::count(P, P + N, 0), N);
-  // FIXME: does not work with QEMU-user.
-  // EXPECT_LT(getResidentMemorySize() - OnStart, Threshold);
 
   memset(P, 1, Size);
   EXPECT_EQ(std::count(P, P + N, 0), 0);