[scudo] Enabled MTE before the first allocator

[vitalybuka]

MemoryTaggingConfig

[vitalybuka]

ping

[pcc]

compiler-rt/lib/scudo/standalone/allocator_config.h

92

So the only difference with DefaultConfig is that this is true? Maybe we should just turn it on in DefaultConfig.

compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp

37

This is presumably because some ctor linked to ScudoCUnitTest or ScudoCxxUnitTest is calling the allocator, correct? This needs a comment.

[vitalybuka]

comments and use DefaultConfig

[vitalybuka]

typo

[vitalybuka]

typo

[pcc]

LGTM

compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp

37

"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."

[crownyanguan]

Hi, when i using cross-build in x86 machine, i found an build error:
/usr/bin/aarch64-linux-gnu-g++ -D_GNU_SOURCE -DSTDC_CONSTANT_MACROS -DSTDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Iprojects/compiler-rt/lib/scudo/standalone -I/llvm-project/compiler-rt/lib/scudo/standalone -Iinclude -I/llvm-project/llvm/include -I/llvm-project/compiler-rt/lib/scudo/standalone/../.. -I/llvm-project/compiler-rt/lib/scudo/standalone/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wmisleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -Wall -std=c++14 -Wno-unused-parameter -O3 -DNDEBUG -march=armv8-a -fno-lto -Werror=conversion -Wall -g -nostdinc++ -fvisibility=hidden -fno-exceptions -Wno-pedantic -fno-lto -O3 -DGWP_ASAN_HOOKS -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -std=c++14 -MD -MT projects/compiler-rt/lib/scudo/standalone/CMakeFiles/clang_rt.scudo_standalone_cxx-aarch64.dir/wrappers_cpp.cpp.o -MF projects/compiler-rt/lib/scudo/standalone/CMakeFiles/clang_rt.scudo_standalone_cxx-aarch64.dir/wrappers_cpp.cpp.o.d -o projects/compiler-rt/lib/scudo/standalone/CMakeFiles/clang_rt.scudo_standalone_cxx-aarch64.dir/wrappers_cpp.cpp.o -c /llvm-project/compiler-rt/lib/scudo/standalone/wrappers_cpp.cp

01:20:30 /tmp/cc8oDmob.s: Assembler messages:
01:20:30 /tmp/cc8oDmob.s:582: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:610: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:618: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:628: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:925: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:953: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:961: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:971: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:1829: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:1857: Error: unknown mnemonic stzg' -- stzg x1,[x1],#16'
01:20:30 /tmp/cc8oDmob.s:1865: Error: unknown or missing operation name at operand 1 -- `dc gzva,x1'
01:20:30 /tmp/cc8oDmob.s:1875: Error: unknown mnemonic stzg' -- stzg x1,[x1],#16'
01:20:30 /tmp/cc8oDmob.s:1950: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:1978: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:1986: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:1996: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:2026: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:2054: Error: unknown mnemonic stzg' -- stzg x1,[x1],#16'
01:20:30 /tmp/cc8oDmob.s:2062: Error: unknown or missing operation name at operand 1 -- `dc gzva,x1'
01:20:30 /tmp/cc8oDmob.s:2072: Error: unknown mnemonic stzg' -- stzg x1,[x1],#16'
01:20:30 /tmp/cc8oDmob.s:14161: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14161: Error: unknown mnemonic stg' -- stg x0,[x0]'
01:20:30 /tmp/cc8oDmob.s:14176: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14176: Error: unknown mnemonic irg' -- irg x22,x25,x22'
01:20:30 /tmp/cc8oDmob.s:14193: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14221: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:14229: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:14239: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:14271: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14271: Error: unknown mnemonic stg' -- stg x1,[x1]'
01:20:30 /tmp/cc8oDmob.s:14375: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14375: Error: unknown mnemonic ldg' -- ldg x8,[x8]'
01:20:30 /tmp/cc8oDmob.s:14429: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14429: Error: unknown mnemonic ldg' -- ldg x1,[x1]'
01:20:30 /tmp/cc8oDmob.s:14502: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14502: Error: unknown mnemonic stg' -- stg x1,[x1]'
01:20:30 /tmp/cc8oDmob.s:14631: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:14659: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:14667: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:14677: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:17421: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:17421: Error: unknown mnemonic irg' -- irg x0,x20,x0'
01:20:30 /tmp/cc8oDmob.s:17437: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:17465: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:17473: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:17483: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:17799: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:17827: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:17835: Error: unknown or missing operation name at operand 1 -- `dc gzva,x0'
01:20:30 /tmp/cc8oDmob.s:17845: Error: unknown mnemonic stzg' -- stzg x0,[x0],#16'
01:20:30 /tmp/cc8oDmob.s:18248: Error: unknown architectural extension `memtag'
01:20:30 /tmp/cc8oDmob.s:18276: Error: unknown mnemonic stzg' -- stzg x1,[x1],#16'
01:20:30 /tmp/cc8oDmob.s:18284: Error: unknown or missing operation name at operand 1 -- `dc gzva,x1'
01:20:30 /tmp/cc8oDmob.s:18294: Error: unknown mnemonic stzg' -- stzg x1,[x1],#16'

[pcc]

This is a known issue with the use of MTE instructions in memtag.h -- they should really be conditional on whether the assembler supports them. For now, please upgrade your assembler.

[crownyanguan]

In D103726#2862258, @pcc wrote:

This is a known issue with the use of MTE instructions in memtag.h -- they should really be conditional on whether the assembler supports them. For now, please upgrade your assembler.

How to update assembly, I build it on a x86 machine.
And, should it be better to be conditional in Makefiles to chose which instructions it produce?

[vitalybuka]

In D103726#2866386, @crownyanguan wrote:

In D103726#2862258, @pcc wrote:

This is a known issue with the use of MTE instructions in memtag.h -- they should really be conditional on whether the assembler supports them. For now, please upgrade your assembler.

How to update assembly, I build it on a x86 machine.
And, should it be better to be conditional in Makefiles to chose which instructions it produce?

Maybe memtag..h till someone volunteer to fix MTE for GCC?
#if clang_major >= 12 && (defined(aarch64) || defined(SCUDO_FUZZ))

[pcc]

Yeah, that should be good enough for now. It won't cover users who have the integrated assembler disabled, but it's better than nothing.

compiler-rt/lib/scudo/standalone/allocator_config.h

 //   // Thread-Specific Data Registry used, shared or exclusive.
 //   template <class A> using TSDRegistryT = TSDRegistrySharedT<A, 8U, 4U>;
 // };
 
 // Default configurations for various platforms.
 
 struct DefaultConfig {
   using SizeClassMap = DefaultSizeClassMap;
-  static const bool MaySupportMemoryTagging = false;
+  static const bool MaySupportMemoryTagging = true;
 
 #if SCUDO_CAN_USE_PRIMARY64
   typedef SizeClassAllocator64<DefaultConfig> Primary;
   static const uptr PrimaryRegionSizeLog = 32U;
   typedef uptr PrimaryCompactPtrT;
   static const uptr PrimaryCompactPtrScale = 0;
   static const bool PrimaryEnableRandomOffset = true;
   static const uptr PrimaryMapSizeIncrement = 1UL << 18;
#endif
   static const u32 SecondaryCacheQuarantineSize = 0U;
   static const u32 SecondaryCacheDefaultMaxEntriesCount = 32U;
   static const uptr SecondaryCacheDefaultMaxEntrySize = 1UL << 19;
   static const s32 SecondaryCacheMinReleaseToOsIntervalMs = INT32_MIN;
   static const s32 SecondaryCacheMaxReleaseToOsIntervalMs = INT32_MAX;
 
   template <class A> using TSDRegistryT = TSDRegistryExT<A>; // Exclusive
 };
-
 struct AndroidConfig {
   using SizeClassMap = AndroidSizeClassMap;
   static const bool MaySupportMemoryTagging = true;
 
 #if SCUDO_CAN_USE_PRIMARY64
   typedef SizeClassAllocator64<AndroidConfig> Primary;
   static const uptr PrimaryRegionSizeLog = 28U;
   typedef u32 PrimaryCompactPtrT;
   static const uptr PrimaryCompactPtrScale = SCUDO_MIN_ALIGNMENT_LOG;
   static const bool PrimaryEnableRandomOffset = true;
   static const uptr PrimaryMapSizeIncrement = 1UL << 18;

compiler-rt/lib/scudo/standalone/tests/scudo_unit_test_main.cpp

 // Match Android's default configuration, which disables Scudo's mismatch
 // allocation check, as it is being triggered by some third party code.
 #if SCUDO_ANDROID
 #define DEALLOC_TYPE_MISMATCH "false"
 #else
 #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:"
          "quarantine_max_chunk_size=512:"
          "dealloc_type_mismatch=" DEALLOC_TYPE_MISMATCH;
 }
 
 // The zxtest library provides a default main function that does the same thing
 // 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();
 }
 #endif

compiler-rt/lib/scudo/standalone/tests/wrappers_cpp_test.cpp

 //===-- wrappers_cpp_test.cpp -----------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
+#include "memtag.h"
 #include "tests/scudo_unit_test.h"
 
 #include <atomic>
 #include <condition_variable>
 #include <mutex>
 #include <thread>
 #include <vector>
 
static void stressNew() {
   }
   while (!V.empty()) {
     delete[] V.back();
     V.pop_back();
   }
 }
 
 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++)
     Threads[I] = std::thread(stressNew);
   {
     std::unique_lock<std::mutex> Lock(Mutex);
     Ready = true;
     Cv.notify_all();