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
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "atomic_helpers.h"
 #include "platform.h"
 
 #if SCUDO_LINUX
@@ -89,9 +90,38 @@
     dieOnMapUnmapError();
 }
 
+static bool madviseNeedsMemset() {
+  uptr Size = getPageSize();
+  char *P = (char *)mmap(0, Size, PROT_READ | PROT_WRITE,
+                         MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (!P)
+    dieOnMapUnmapError(errno == ENOMEM);
+  *P = -1;
+  while (madvise(P, Size, MADV_DONTNEED) == -1 && errno == EAGAIN) {
+  }
+  bool R = (*P != 0);
+  if (munmap(P, Size) != 0)
+    dieOnMapUnmapError();
+  return R;
+}
+
+static bool madviseNeedsMemsetCached() {
+  static atomic_u8 NeedsMemset;
+  u8 Z = atomic_load_relaxed(&NeedsMemset);
+  if (!Z) {
+    Z = madviseNeedsMemset() ? 1 : 2;
+    atomic_store_relaxed(&NeedsMemset, Z);
+  }
+  return Z == 1;
+}
+
 void releasePagesToOS(uptr BaseAddress, uptr Offset, uptr Size,
                       UNUSED MapPlatformData *Data) {
   void *Addr = reinterpret_cast<void *>(BaseAddress + Offset);
+  if (madviseNeedsMemsetCached()) {
+    // Workaround for QEMU-user which ignores MADV_DONTNEED.
+    memset(Addr, 0, Size);
+  }
   while (madvise(Addr, Size, MADV_DONTNEED) == -1 && errno == EAGAIN) {
   }
 }