Index: lib/asan/asan_allocator.h
===================================================================
--- lib/asan/asan_allocator.h
+++ lib/asan/asan_allocator.h
@@ -114,6 +114,11 @@
 # if defined(__powerpc64__)
 const uptr kAllocatorSpace =  0xa0000000000ULL;
 const uptr kAllocatorSize  =  0x20000000000ULL;  // 2T.
+# elif defined(__aarch64__)
+// AArch64/SANITIZIER_CAN_USER_ALLOCATOR64 is only for 42-bit VMA
+// so no need to different values for different VMA.
+const uptr kAllocatorSpace =  0x10000000000ULL;
+const uptr kAllocatorSize  =  0x10000000000ULL;  // 3T.
 # else
 const uptr kAllocatorSpace = 0x600000000000ULL;
 const uptr kAllocatorSize  =  0x40000000000ULL;  // 4T.
Index: lib/asan/asan_mapping.h
===================================================================
--- lib/asan/asan_mapping.h
+++ lib/asan/asan_mapping.h
@@ -80,6 +80,13 @@
 // || `[0x1000000000, 0x11ffffffff]` || lowshadow  ||
 // || `[0x0000000000, 0x0fffffffff]` || lowmem     ||
 //
+// Default Linux/AArch64 (42-bit VMA) mapping:
+// || `[0x10000000000, 0x3ffffffffff]` || highmem    ||
+// || `[0x0a000000000, 0x0ffffffffff]` || highshadow ||
+// || `[0x09000000000, 0x09fffffffff]` || shadowgap  ||
+// || `[0x08000000000, 0x08fffffffff]` || lowshadow  ||
+// || `[0x00000000000, 0x07fffffffff]` || lowmem     ||
+//
 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
 // || `[0x500000000000, 0x7fffffffffff]` || HighMem    ||
 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
@@ -111,7 +118,11 @@
 static const u64 kIosShadowOffset64 = 0x130000000;
 static const u64 kIosSimShadowOffset32 = 1ULL << 30;
 static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
+#if SANITIZER_AARCH64_VMA == 39
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
+#elif SANITIZER_AARCH64_VMA == 42
+static const u64 kAArch64_ShadowOffset64 = 1ULL << 39;
+#endif
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
Index: lib/sanitizer_common/sanitizer_platform.h
===================================================================
--- lib/sanitizer_common/sanitizer_platform.h
+++ lib/sanitizer_common/sanitizer_platform.h
@@ -81,13 +81,24 @@
 # define SANITIZER_X32 0
 #endif
 
+// VMA size definition for architecture that support multiple sizes.
+// AArch64 has 3 VMA sizes: 39, 42 and 48.
+#if SANITIZER_LINUX && defined(__aarch64__)
+# if SANITIZER_AARCH64_VMA != 39 && SANITIZER_AARCH64_VMA != 42
+#  error "invalid SANITIZER_AARCH64_VMA size"
+# endif
+# ifndef SANITIZER_AARCH64_VMA
+#  define SANITIZER_AARCH64_VMA 39
+# endif
+#endif
+
 // By default we allow to use SizeClassAllocator64 on 64-bit platform.
 // But in some cases (e.g. AArch64's 39-bit address space) SizeClassAllocator64
 // does not work well and we need to fallback to SizeClassAllocator32.
 // For such platforms build this code with -DSANITIZER_CAN_USE_ALLOCATOR64=0 or
 // change the definition of SANITIZER_CAN_USE_ALLOCATOR64 here.
 #ifndef SANITIZER_CAN_USE_ALLOCATOR64
-# if defined(__aarch64__) || defined(__mips64)
+# if defined(__mips64) || (defined(__aarch64__) && SANITIZER_AARCH64_VMA == 39)
 #  define SANITIZER_CAN_USE_ALLOCATOR64 0
 # else
 #  define SANITIZER_CAN_USE_ALLOCATOR64 (SANITIZER_WORDSIZE == 64)
@@ -99,7 +110,11 @@
 // e.g. on AArch64 it is most likely (1ULL << 39). Larger values will still work
 // but will consume more memory for TwoLevelByteMap.
 #if defined(__aarch64__)
-# define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 39)
+# if SANITIZER_AARCH64_VMA == 39
+#  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 39)
+# elif SANITIZER_AARCH64_VMA == 42
+#  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 42)
+# endif
 #elif defined(__mips__)
 # define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 40)
 #else
@@ -130,7 +145,7 @@
 #define SANITIZER_USES_UID16_SYSCALLS 0
 #endif
 
-#if defined(__mips__) || defined(__aarch64__)
+#if defined(__mips__) || (defined(__aarch64__) && SANITIZER_AARCH64_VMA == 39)
 # define SANITIZER_POINTER_FORMAT_LENGTH FIRST_32_SECOND_64(8, 10)
 #else
 # define SANITIZER_POINTER_FORMAT_LENGTH FIRST_32_SECOND_64(8, 12)