Let's find out what's up with the TSAN bot test failures.

tests/MathTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkEndian.h"
 #include "SkFloatBits.h"
@@ skipping 519 matching lines @@
 
         (void)SkCLZ(numer);
         (void)SkCLZ(denom);
 
         REPORTER_ASSERT(reporter, result != (SkFixed)SK_NaN32);
         if (check > SK_MaxS32) {
             check = SK_MaxS32;
         } else if (check < -SK_MaxS32) {
             check = SK_MinS32;
         }
+        if (result != (int32_t)check) {
+            ERRORF(reporter, "\nFixed Divide: %8x / %8x -> %8x %8x\n", numer, denom, result, check);
+        }
         REPORTER_ASSERT(reporter, result == (int32_t)check);
     }
 
     test_blend(reporter);
 
     if (false) test_floor(reporter);
 
     // disable for now
     if (false) test_blend31();  // avoid bit rot, suppress warning
 
@@ skipping 101 matching lines @@
     test_divmod<int16_t>(r);
 }
 
 DEF_TEST(divmod_s32, r) {
     test_divmod<int32_t>(r);
 }
 
 DEF_TEST(divmod_s64, r) {
     test_divmod<int64_t>(r);
 }