Index: lib/sanitizer_common/sanitizer_posix.cc
===================================================================
--- lib/sanitizer_common/sanitizer_posix.cc
+++ lib/sanitizer_common/sanitizer_posix.cc
@@ -76,17 +76,79 @@
 }
 #endif  // SANITIZER_WORDSIZE == 32
 
+#if defined(__powerpc64__) && SANITIZER_LINUX
+
+// Compare two decimal digit strings by their numeric value.
+// The strings are terminated by any non-digit character.
+// Empty strings are allowed and are treated as zero.
+// Return -1, 0 or 1 when a is less than, equal to or greater than b
+// respectively.
+// Update a and b to point just past the end of the digit strings.
+static int cmp_decimal(const char *&a, const char *&b) {
+  // Skip leading zeros.
+  while (*a == '0')
+    ++a;
+  while (*b == '0')
+    ++b;
+  // Compare string lengths.
+  size_t la = 0, lb = 0;
+  while (a[la] >= '0' && a[la] <= '9')
+    ++la;
+  while (b[lb] >= '0' && b[lb] <= '9')
+    ++lb;
+  if (la != lb)
+    return la > lb ? 1 : -1;
+  // Compare strings lexicographically.
+  for (; la--; ++a, ++b)
+    if (*a != *b)
+      return *a > *b ? 1 : -1;
+  return 0;
+}
+
+// Compare two version strings of the form "x", "x.y", "x.y.z" etc.
+// The strings are terminated by any non-digit, non-dot character.
+// Any missing trailing components are treated as zero.
+// Return -1, 0 or 1 when a is less than, equal to or greater than b
+// respectively.
+static int cmp_version(const char *a, const char *b) {
+  while (true) {
+    int ret = cmp_decimal(a, b);
+    if (ret)
+      return ret;
+    if (*a != '.' && *b != '.')
+      return 0;
+    if (*a == '.')
+      ++a;
+    if (*b == '.')
+      ++b;
+  }
+}
+
+#endif // defined(__powerpc64__) && SANITIZER_LINUX
+
 uptr GetMaxVirtualAddress() {
 #if SANITIZER_WORDSIZE == 64
-# if defined(__powerpc64__) && defined(__BIG_ENDIAN__)
+# if defined(__powerpc64__)
   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
   // We somehow need to figure out which one we are using now and choose
   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
   // of the address space, so simply checking the stack address is not enough.
+#  if SANITIZER_LINUX
+  // Linux switched to 46-bit addressing in version 3.7.
+  struct utsname uname_info;
+  if (uname(&uname_info) == 0) {
+    if (cmp_version(uname_info.release, "3.7") >= 0)
+      return (1ULL << 46) - 1;  // 0x00003fffffffffffUL
+    else
+      return (1ULL << 44) - 1;  // 0x00000fffffffffffUL
+  }
+#  endif
+#  if defined(__BIG_ENDIAN__)
   return (1ULL << 44) - 1;  // 0x00000fffffffffffUL
-# elif defined(__powerpc64__) && defined(__LITTLE_ENDIAN__)
+#  else
   return (1ULL << 46) - 1;  // 0x00003fffffffffffUL
+#  endif
 # elif defined(__aarch64__)
   return (1ULL << 39) - 1;
 # else