tsan: protect trace memory range on startup

so that user does not map something there ahead of us

llvm-svn: 223456

diff --git a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
index 46b648c..4612741 100644 (file)
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
@@ -324,6 +324,9 @@ static void CheckAndProtect() {
   ProtectRange(kLoAppMemEnd, kShadowBeg);
   ProtectRange(kShadowEnd, kMetaShadowBeg);
   ProtectRange(kMetaShadowEnd, kTraceMemBeg);
+  // Memory for traces is mapped lazily in MapThreadTrace.
+  // Protect the whole range for now, so that user does not map something here.
+  ProtectRange(kTraceMemBeg, kTraceMemEnd);
   ProtectRange(kTraceMemEnd, kHeapMemBeg);
   ProtectRange(kHeapMemEnd + PrimaryAllocator::AdditionalSize(), kHiAppMemBeg);
 }