Index: lib/sanitizer_common/sanitizer_common_syscalls.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_syscalls.inc
+++ lib/sanitizer_common/sanitizer_common_syscalls.inc
@@ -1443,6 +1443,12 @@
 
 POST_SYSCALL(fchown)(long res, long fd, long user, long group) {}
 
+// Syscalls below are only available on 64-bit target if CONFIG_COMPAT
+// (which enables CONFIG_HAVE_UID16) is selected in kernel defconfig.
+// These syscalls implementations are needed for 32-bit (compat)
+// applications on 64-bit target. They will not be used by 64-bit
+// applications.
+#if SANITIZER_WORDSIZE == 32
 PRE_SYSCALL(chown16)(const void *filename, long user, long group) {
   if (filename)
     PRE_READ(filename,
@@ -1552,6 +1558,7 @@
 PRE_SYSCALL(getegid16)() {}
 
 POST_SYSCALL(getegid16)(long res) {}
+#endif // SANITIZER_WORDSIZE == 32
 
 PRE_SYSCALL(utime)(void *filename, void *times) {}
 
Index: lib/sanitizer_common/sanitizer_platform_limits_posix.cc
===================================================================
--- lib/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ lib/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -1006,7 +1006,7 @@
 CHECK_TYPE_SIZE(__kernel_uid_t);
 CHECK_TYPE_SIZE(__kernel_gid_t);
 
-#if !defined(__aarch64__)
+#if SANITIZER_WORDSIZE == 32
 CHECK_TYPE_SIZE(__kernel_old_uid_t);
 CHECK_TYPE_SIZE(__kernel_old_gid_t);
 #endif