Index: lib/tsan/rtl/tsan_external.cc
===================================================================
--- lib/tsan/rtl/tsan_external.cc
+++ lib/tsan/rtl/tsan_external.cc
@@ -58,7 +58,7 @@
   ThreadState *thr = cur_thread();
   thr->external_tag = (uptr)tag;
   FuncEntry(thr, (uptr)caller_pc);
-  MemoryRead(thr, CALLERPC, (uptr)addr, kSizeLog8);
+  MemoryRead(thr, CALLERPC, (uptr)addr, kSizeLog1);
   FuncExit(thr);
   thr->external_tag = 0;
 }
@@ -69,7 +69,7 @@
   ThreadState *thr = cur_thread();
   thr->external_tag = (uptr)tag;
   FuncEntry(thr, (uptr)caller_pc);
-  MemoryWrite(thr, CALLERPC, (uptr)addr, kSizeLog8);
+  MemoryWrite(thr, CALLERPC, (uptr)addr, kSizeLog1);
   FuncExit(thr);
   thr->external_tag = 0;
 }