Index: lib/msan/msan.h
===================================================================
--- lib/msan/msan.h
+++ lib/msan/msan.h
@@ -66,15 +66,19 @@
 
 #elif SANITIZER_LINUX && defined(__aarch64__)
 
-// The mapping describes both 39-bits and 42-bits.  AArch64 maps:
-// - 0x00000000000-0x00010000000: 39/42-bits program own segments
-// - 0x05500000000-0x05600000000: 39-bits PIE program segments
-// - 0x07f80000000-0x07fffffffff: 39-bits libraries segments
-// - 0x2aa00000000-0x2ab00000000: 42-bits PIE program segments
-// - 0x3ff00000000-0x3ffffffffff: 42-bits libraries segments
+// The mapping describes both 39-bits, 42-bits, and 48-bits VMA.  AArch64
+// maps:
+// - 0x0000000000000-0x0000010000000: 39/42/48-bits program own segments
+// - 0x0005500000000-0x0005600000000: 39-bits PIE program segments
+// - 0x0007f80000000-0x0007fffffffff: 39-bits libraries segments
+// - 0x002aa00000000-0x002ab00000000: 42-bits PIE program segments
+// - 0x003ff00000000-0x003ffffffffff: 42-bits libraries segments
+// - 0x0aaaaa0000000-0x0aaab00000000: 48-bits PIE program segments
+// - 0xffff000000000-0x1000000000000: 48-bits libraries segments
 // It is fragmented in multiples segments to increase the memory available
 // on 42-bits (12.21% of total VMA available for 42-bits and 13.28 for
-// 39 bits).
+// 39 bits). The 48-bits segments only cover the usual PIE/default segments
+// plus some more segments (262144GB total, 0.39% total VMA).
 const MappingDesc kMemoryLayout[] = {
     {0x00000000000ULL, 0x01000000000ULL, MappingDesc::INVALID, "invalid"},
     {0x01000000000ULL, 0x02000000000ULL, MappingDesc::SHADOW, "shadow-2"},
@@ -115,6 +119,42 @@
     {0x3D000000000ULL, 0x3E000000000ULL, MappingDesc::SHADOW, "shadow-8"},
     {0x3E000000000ULL, 0x3F000000000ULL, MappingDesc::ORIGIN, "origin-8"},
     {0x3F000000000ULL, 0x40000000000ULL, MappingDesc::APP, "app-9"},
+    // The mappings below are used only for 48-bits VMA.
+    // TODO(unknown): 48-bit mapping ony covers the usual PIE, non-PIE
+    // segments and some more segments totalizing 262144GB of VMA (which cover
+    // only 0.32% of all 48-bit VMA). Memory avaliability can be increase by
+    // adding multiple application segments like 39 and 42 mapping.
+    {0x0040000000000ULL, 0x0041000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0041000000000ULL, 0x0042000000000ULL, MappingDesc::APP, "app-10"},
+    {0x0042000000000ULL, 0x0047000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0047000000000ULL, 0x0048000000000ULL, MappingDesc::SHADOW, "shadow-10"},
+    {0x0048000000000ULL, 0x0049000000000ULL, MappingDesc::ORIGIN, "origin-10"},
+    {0x0049000000000ULL, 0x0050000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0050000000000ULL, 0x0051000000000ULL, MappingDesc::APP, "app-11"},
+    {0x0051000000000ULL, 0x0056000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0056000000000ULL, 0x0057000000000ULL, MappingDesc::SHADOW, "shadow-11"},
+    {0x0057000000000ULL, 0x0058000000000ULL, MappingDesc::ORIGIN, "origin-11"},
+    {0x0058000000000ULL, 0x0059000000000ULL, MappingDesc::APP, "app-12"},
+    {0x0059000000000ULL, 0x005E000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x005E000000000ULL, 0x005F000000000ULL, MappingDesc::SHADOW, "shadow-12"},
+    {0x005F000000000ULL, 0x0060000000000ULL, MappingDesc::ORIGIN, "origin-12"},
+    {0x0060000000000ULL, 0x0061000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0061000000000ULL, 0x0062000000000ULL, MappingDesc::APP, "app-13"},
+    {0x0062000000000ULL, 0x0067000000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0067000000000ULL, 0x0068000000000ULL, MappingDesc::SHADOW, "shadow-13"},
+    {0x0068000000000ULL, 0x0069000000000ULL, MappingDesc::ORIGIN, "origin-13"},
+    {0x0069000000000ULL, 0x0AAAAA0000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0AAAAA0000000ULL, 0x0AAAB00000000ULL, MappingDesc::APP, "app-14"},
+    {0x0AAAB00000000ULL, 0x0AACAA0000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0AACAA0000000ULL, 0x0AACB00000000ULL, MappingDesc::SHADOW, "shadow-14"},
+    {0x0AACB00000000ULL, 0x0AADAA0000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0AADAA0000000ULL, 0x0AADB00000000ULL, MappingDesc::ORIGIN, "origin-14"},
+    {0x0AADB00000000ULL, 0x0FF9F00000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0FF9F00000000ULL, 0x0FFA000000000ULL, MappingDesc::SHADOW, "shadow-15"},
+    {0x0FFA000000000ULL, 0x0FFAF00000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0FFAF00000000ULL, 0x0FFB000000000ULL, MappingDesc::ORIGIN, "origin-15"},
+    {0x0FFB000000000ULL, 0x0FFFF00000000ULL, MappingDesc::INVALID, "invalid"},
+    {0x0FFFF00000000ULL, 0x1000000000000ULL, MappingDesc::APP, "app-15"},
 };
 # define MEM_TO_SHADOW(mem) ((uptr)mem ^ 0x6000000000ULL)
 # define SHADOW_TO_ORIGIN(shadow) (((uptr)(shadow)) + 0x1000000000ULL)
Index: lib/msan/msan_linux.cc
===================================================================
--- lib/msan/msan_linux.cc
+++ lib/msan/msan_linux.cc
@@ -66,7 +66,8 @@
     }
     if ((uptr)addr != beg) {
       uptr end = beg + size - 1;
-      Printf("FATAL: Cannot protect memory range %p - %p.\n", beg, end);
+      Printf("FATAL: Cannot protect memory range %p - %p (%s).\n", beg, end,
+             name);
       return false;
     }
   }
Index: test/msan/mmap.cc
===================================================================
--- test/msan/mmap.cc
+++ test/msan/mmap.cc
@@ -39,6 +39,12 @@
     {0x2E000000000ULL, 0x2F000000000ULL},
     {0x3B000000000ULL, 0x3C000000000ULL},
     {0x3F000000000ULL, 0x40000000000ULL},
+    {0x0041000000000ULL, 0x0042000000000ULL},
+    {0x0050000000000ULL, 0x0051000000000ULL},
+    {0x0058000000000ULL, 0x0059000000000ULL},
+    {0x0061000000000ULL, 0x0062000000000ULL},
+    {0x0AAAAA0000000ULL, 0x0AAAB00000000ULL},
+    {0x0FFFF00000000ULL, 0x1000000000000ULL},
   };
   const size_t mappingsSize = sizeof (mappings) / sizeof (mappings[0]);