From 3d8f49a6bf6eb0912e66c43a2b3fe890ca385b74 Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Tue, 4 Sep 2018 23:26:08 +0000
Subject: [PATCH] [hwasan] add a unique id to a thread and add debug prints for
 thread creation/destruction

llvm-svn: 341428
---
 compiler-rt/lib/hwasan/hwasan_flags.inc              |  2 ++
 compiler-rt/lib/hwasan/hwasan_thread.cc              | 11 +++++++++++
 compiler-rt/lib/hwasan/hwasan_thread.h               |  3 +++
 compiler-rt/test/hwasan/TestCases/many-threads-uaf.c |  9 ++++++++-
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/hwasan/hwasan_flags.inc b/compiler-rt/lib/hwasan/hwasan_flags.inc
index cd04f53..fa54242 100644
--- a/compiler-rt/lib/hwasan/hwasan_flags.inc
+++ b/compiler-rt/lib/hwasan/hwasan_flags.inc
@@ -17,6 +17,8 @@
 // HWASAN_FLAG(Type, Name, DefaultValue, Description)
 // See COMMON_FLAG in sanitizer_flags.inc for more details.
 
+HWASAN_FLAG(bool, verbose_threads, false,
+            "inform on thread creation/destruction")
 HWASAN_FLAG(bool, tag_in_malloc, true, "")
 HWASAN_FLAG(bool, tag_in_free, true, "")
 HWASAN_FLAG(bool, print_stats, false, "")
diff --git a/compiler-rt/lib/hwasan/hwasan_thread.cc b/compiler-rt/lib/hwasan/hwasan_thread.cc
index 653c99f..6bf3ad4 100644
--- a/compiler-rt/lib/hwasan/hwasan_thread.cc
+++ b/compiler-rt/lib/hwasan/hwasan_thread.cc
@@ -59,6 +59,7 @@ void Thread::RemoveFromThreadList(Thread *t) {
 
 Thread *Thread::Create(thread_callback_t start_routine,
                                void *arg) {
+  static u64 unique_id;
   uptr PageSize = GetPageSizeCached();
   uptr size = RoundUpTo(sizeof(Thread), PageSize);
   Thread *thread = (Thread*)MmapOrDie(size, __func__);
@@ -68,6 +69,7 @@ Thread *Thread::Create(thread_callback_t start_routine,
   thread->random_state_ = flags()->random_tags ? RandomSeed() : 0;
   if (auto sz = flags()->heap_history_size)
     thread->heap_allocations_ = RingBuffer<HeapAllocationRecord>::New(sz);
+  thread->unique_id_ = unique_id++;
   InsertIntoThreadList(thread);
   return thread;
 }
@@ -99,6 +101,8 @@ void Thread::Init() {
     CHECK(MemIsApp(stack_bottom_));
     CHECK(MemIsApp(stack_top_ - 1));
   }
+  if (flags()->verbose_threads)
+    Print("Creating  ");
 }
 
 void Thread::ClearShadowForThreadStackAndTLS() {
@@ -109,6 +113,8 @@ void Thread::ClearShadowForThreadStackAndTLS() {
 }
 
 void Thread::Destroy() {
+  if (flags()->verbose_threads)
+    Print("Destroying");
   malloc_storage().CommitBack();
   ClearShadowForThreadStackAndTLS();
   RemoveFromThreadList(this);
@@ -119,6 +125,11 @@ void Thread::Destroy() {
   DTLS_Destroy();
 }
 
+void Thread::Print(const char *Prefix) {
+  Printf("%s: thread %p id: %zd stack: [%p,%p) tls: [%p,%p)\n", Prefix, this,
+         unique_id_, stack_bottom(), stack_top(), tls_begin(), tls_end());
+}
+
 static u32 xorshift(u32 state) {
   state ^= state << 13;
   state ^= state >> 17;
diff --git a/compiler-rt/lib/hwasan/hwasan_thread.h b/compiler-rt/lib/hwasan/hwasan_thread.h
index 11ecf2f..0172935 100644
--- a/compiler-rt/lib/hwasan/hwasan_thread.h
+++ b/compiler-rt/lib/hwasan/hwasan_thread.h
@@ -84,6 +84,7 @@ class Thread {
   // via mmap() and *must* be valid in zero-initialized state.
   void SetThreadStackAndTls();
   void ClearShadowForThreadStackAndTLS();
+  void Print(const char *prefix);
   thread_callback_t start_routine_;
   void *arg_;
   uptr stack_top_;
@@ -107,6 +108,8 @@ class Thread {
   static SpinMutex thread_list_mutex;
   static Thread *main_thread;
 
+  u64 unique_id_;  // counting from zero.
+
   u32 tagging_disabled_;  // if non-zero, malloc uses zero tag in this thread.
 
   ThreadStartArg thread_start_arg_;
diff --git a/compiler-rt/test/hwasan/TestCases/many-threads-uaf.c b/compiler-rt/test/hwasan/TestCases/many-threads-uaf.c
index 7ee3554..4f58b3e 100644
--- a/compiler-rt/test/hwasan/TestCases/many-threads-uaf.c
+++ b/compiler-rt/test/hwasan/TestCases/many-threads-uaf.c
@@ -1,4 +1,4 @@
-// RUN: %clang_hwasan %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang_hwasan %s -o %t && not %env_hwasan_opts=verbose_threads=1 %run %t 2>&1 | FileCheck %s
 // REQUIRES: stable-runtime
 
 #include <pthread.h>
@@ -14,6 +14,13 @@ void *BoringThread(void *arg) {
   return NULL;
 }
 
+// CHECK: Creating  : thread {{.*}} id: 0
+// CHECK: Creating  : thread {{.*}} id: 1
+// CHECK: Destroying: thread {{.*}} id: 1
+// CHECK: Creating  : thread {{.*}} id: 1100
+// CHECK: Destroying: thread {{.*}} id: 1100
+// CHECK: Creating  : thread {{.*}} id: 1101
+
 void *UAFThread(void *arg) {
   char * volatile x = (char*)malloc(10);
   fprintf(stderr, "ZZZ %p\n", x);
-- 
2.7.4