[compiler-rt] 533abb7 - [scudo] Enabled MTE before the first allocator

[Vitaly Buka via llvm-commits]

Author: Vitaly Buka
Date: 2021-06-23T23:01:26-07:00
New Revision: 533abb7ecf1c0e80429ad7cd850e9720d2b2ae1c

URL: https://github.com/llvm/llvm-project/commit/533abb7ecf1c0e80429ad7cd850e9720d2b2ae1c
DIFF: https://github.com/llvm/llvm-project/commit/533abb7ecf1c0e80429ad7cd850e9720d2b2ae1c.diff

LOG: [scudo] Enabled MTE before the first allocator

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D103726

Added: 
    

Modified: 
    compiler-rt/lib/scudo/standalone/allocator_config.h
    compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp
    compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/scudo/standalone/allocator_config.h b/compiler-rt/lib/scudo/standalone/allocator_config.h
index 7f556360c6245..e6f46b511dbfa 100644
--- a/compiler-rt/lib/scudo/standalone/allocator_config.h
+++ b/compiler-rt/lib/scudo/standalone/allocator_config.h
@@ -60,7 +60,7 @@ namespace scudo {
 
 struct DefaultConfig {
   using SizeClassMap = DefaultSizeClassMap;
-  static const bool MaySupportMemoryTagging = false;
+  static const bool MaySupportMemoryTagging = true;
 
 #if SCUDO_CAN_USE_PRIMARY64
   typedef SizeClassAllocator64<DefaultConfig> Primary;
@@ -87,7 +87,6 @@ struct DefaultConfig {
 
   template <class A> using TSDRegistryT = TSDRegistryExT<A>; // Exclusive
 };
-
 struct AndroidConfig {
   using SizeClassMap = AndroidSizeClassMap;
   static const bool MaySupportMemoryTagging = true;

diff  --git a/compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp b/compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp
index 1983b80ac0ca4..fbfefa5c93d54 100644
--- a/compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp
@@ -17,12 +17,27 @@
 #define DEALLOC_TYPE_MISMATCH "true"
 #endif
 
+static void EnableMemoryTaggingIfSupported() {
+  if (!scudo::archSupportsMemoryTagging())
+    return;
+  static bool Done = []() {
+    if (!scudo::systemDetectsMemoryTagFaultsTestOnly())
+      scudo::enableSystemMemoryTaggingTestOnly();
+    return true;
+  }();
+  (void)Done;
+}
+
 // This allows us to turn on/off a Quarantine for specific tests. The Quarantine
 // parameters are on the low end, to avoid having to loop excessively in some
 // tests.
 bool UseQuarantine = true;
 extern "C" __attribute__((visibility("default"))) const char *
 __scudo_default_options() {
+  // The wrapper tests initialize the global allocator early, before main(). We
+  // need to have Memory Tagging enabled before that happens or the allocator
+  // will disable the feature entirely.
+  EnableMemoryTaggingIfSupported();
   if (!UseQuarantine)
     return "dealloc_type_mismatch=" DEALLOC_TYPE_MISMATCH;
   return "quarantine_size_kb=256:thread_local_quarantine_size_kb=128:"
@@ -34,8 +49,7 @@ __scudo_default_options() {
 // for Fuchsia builds.
 #if !SCUDO_FUCHSIA
 int main(int argc, char **argv) {
-  if (scudo::archSupportsMemoryTagging())
-    scudo::enableSystemMemoryTaggingTestOnly();
+  EnableMemoryTaggingIfSupported();
   testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }

diff  --git a/compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp b/compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp
index 9df06dcdf1420..64a0917d47738 100644
--- a/compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "memtag.h"
 #include "tests/scudo_unit_test.h"
 
 #include <atomic>
@@ -107,6 +108,11 @@ static void stressNew() {
 }
 
 TEST(ScudoWrappersCppTest, ThreadedNew) {
+#if !SCUDO_ANDROID
+  // TODO: Investigate why libc sometimes crashes with tag missmatch in
+  // __pthread_clockjoin_ex.
+  scudo::ScopedDisableMemoryTagChecks NoTags;
+#endif
   Ready = false;
   std::thread Threads[32];
   for (size_t I = 0U; I < sizeof(Threads) / sizeof(Threads[0]); I++)