[compiler-rt] r191899 - tsan: fix false positive in localtime()

[Dmitry Vyukov]

Author: dvyukov
Date: Thu Oct  3 09:12:09 2013
New Revision: 191899

URL: http://llvm.org/viewvc/llvm-project?rev=191899&view=rev
Log:
tsan: fix false positive in localtime()


Modified:
    compiler-rt/trunk/lib/msan/msan_interceptors.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc

Modified: compiler-rt/trunk/lib/msan/msan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_interceptors.cc?rev=191899&r1=191898&r2=191899&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/msan/msan_interceptors.cc Thu Oct  3 09:12:09 2013
@@ -1126,6 +1126,8 @@ struct MSanInterceptorContext {
   __msan_unpoison(ptr, size)
 #define COMMON_INTERCEPTOR_READ_RANGE(ctx, ptr, size) \
   CHECK_UNPOISONED_CTX(ctx, ptr, size)
+#define COMMON_INTERCEPTOR_INITIALIZE_RANGE(ctx, ptr, size) \
+  __msan_unpoison(ptr, size)
 #define COMMON_INTERCEPTOR_ENTER(ctx, func, ...)              \
   if (msan_init_is_running) return REAL(func)(__VA_ARGS__);   \
   MSanInterceptorContext msan_ctx = {IsInInterceptorScope()}; \

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc?rev=191899&r1=191898&r2=191899&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc Thu Oct  3 09:12:09 2013
@@ -15,6 +15,7 @@
 //   COMMON_INTERCEPTOR_ENTER
 //   COMMON_INTERCEPTOR_READ_RANGE
 //   COMMON_INTERCEPTOR_WRITE_RANGE
+//   COMMON_INTERCEPTOR_INITIALIZE_RANGE
 //   COMMON_INTERCEPTOR_FD_ACQUIRE
 //   COMMON_INTERCEPTOR_FD_RELEASE
 //   COMMON_INTERCEPTOR_SET_THREAD_NAME
@@ -28,6 +29,10 @@
 #define va_copy(dst, src) ((dst) = (src))
 #endif // _WIN32
 
+#ifndef COMMON_INTERCEPTOR_INITIALIZE_RANGE
+# define COMMON_INTERCEPTOR_INITIALIZE_RANGE(ctx, p, size)
+#endif
+
 #if SANITIZER_INTERCEPT_STRCMP
 static inline int CharCmpX(unsigned char c1, unsigned char c2) {
   return (c1 == c2) ? 0 : (c1 < c2) ? -1 : 1;
@@ -405,9 +410,12 @@ INTERCEPTOR(unsigned long, time, unsigne
 #if SANITIZER_INTERCEPT_LOCALTIME_AND_FRIENDS
 static void unpoison_tm(void *ctx, __sanitizer_tm *tm) {
   COMMON_INTERCEPTOR_WRITE_RANGE(ctx, tm, sizeof(*tm));
-  if (tm->tm_zone)
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, tm->tm_zone,
-                                   REAL(strlen(tm->tm_zone)) + 1);
+  if (tm->tm_zone) {
+    // Can not use COMMON_INTERCEPTOR_WRITE_RANGE here, because tm->tm_zone
+    // can point to shared memory and tsan would report a data race.
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(ctx, tm->tm_zone,
+                                        REAL(strlen(tm->tm_zone)) + 1);
+  }
 }
 
 INTERCEPTOR(__sanitizer_tm *, localtime, unsigned long *timep) {