diff --git a/src/mem/physical.cc b/src/mem/physical.cc
index cae37a05bf..06f2cdc003 100644
--- a/src/mem/physical.cc
+++ b/src/mem/physical.cc
@@ -50,6 +50,7 @@
 #include <iostream>
 #include <string>
 
+#include "base/intmath.hh"
 #include "base/trace.hh"
 #include "debug/AddrRanges.hh"
 #include "debug/Checkpoint.hh"
@@ -81,7 +82,8 @@ PhysicalMemory::PhysicalMemory(const std::string& _name,
                                const std::string& shared_backstore,
                                bool auto_unlink_shared_backstore) :
     _name(_name), size(0), mmapUsingNoReserve(mmap_using_noreserve),
-    sharedBackstore(shared_backstore), sharedBackstoreSize(0)
+    sharedBackstore(shared_backstore), sharedBackstoreSize(0),
+    pageSize(sysconf(_SC_PAGE_SIZE))
 {
     // Register cleanup callback if requested.
     if (auto_unlink_shared_backstore && !sharedBackstore.empty()) {
@@ -217,7 +219,9 @@ PhysicalMemory::createBackingStore(
     } else {
         // Newly create backstore will be located after previous one.
         map_offset = sharedBackstoreSize;
-        sharedBackstoreSize += range.size();
+        // mmap requires the offset to be multiple of page, so we need to
+        // upscale the range size.
+        sharedBackstoreSize += roundUp(range.size(), pageSize);
         DPRINTF(AddrRanges, "Sharing backing store as %s at offset %llu\n",
                 sharedBackstore.c_str(), (uint64_t)map_offset);
         shm_fd = shm_open(sharedBackstore.c_str(), O_CREAT | O_RDWR, 0666);
diff --git a/src/mem/physical.hh b/src/mem/physical.hh
index 3a976eddcc..4997d80323 100644
--- a/src/mem/physical.hh
+++ b/src/mem/physical.hh
@@ -156,6 +156,8 @@ class PhysicalMemory : public Serializable
     const std::string sharedBackstore;
     uint64_t sharedBackstoreSize;
 
+    long pageSize;
+
     // The physical memory used to provide the memory in the simulated
     // system
     std::vector<BackingStoreEntry> backingStore;