1 files changed, 30 insertions, 2 deletions

diff --git a/libsanitizer/asan/asan_allocator.cpp b/libsanitizer/asan/asan_allocator.cpp
index 58b496a..7c8bb50 100644
--- a/libsanitizer/asan/asan_allocator.cpp
+++ b/libsanitizer/asan/asan_allocator.cpp
@@ -476,7 +476,7 @@ struct Allocator {
       return false;
     if (m->Beg() != addr) return false;
     AsanThread *t = GetCurrentThread();
-    m->SetAllocContext(t ? t->tid() : 0, StackDepotPut(*stack));
+    m->SetAllocContext(t ? t->tid() : kMainTid, StackDepotPut(*stack));
     return true;
   }
 
@@ -570,7 +570,7 @@ struct Allocator {
     m->SetUsedSize(size);
     m->user_requested_alignment_log = user_requested_alignment_log;
 
-    m->SetAllocContext(t ? t->tid() : 0, StackDepotPut(*stack));
+    m->SetAllocContext(t ? t->tid() : kMainTid, StackDepotPut(*stack));
 
     uptr size_rounded_down_to_granularity =
         RoundDownTo(size, SHADOW_GRANULARITY);
@@ -1183,6 +1183,34 @@ IgnoreObjectResult IgnoreObjectLocked(const void *p) {
   m->lsan_tag = __lsan::kIgnored;
   return kIgnoreObjectSuccess;
 }
+
+void GetAdditionalThreadContextPtrs(ThreadContextBase *tctx, void *ptrs) {
+  // Look for the arg pointer of threads that have been created or are running.
+  // This is necessary to prevent false positive leaks due to the AsanThread
+  // holding the only live reference to a heap object.  This can happen because
+  // the `pthread_create()` interceptor doesn't wait for the child thread to
+  // start before returning and thus loosing the the only live reference to the
+  // heap object on the stack.
+
+  __asan::AsanThreadContext *atctx =
+      reinterpret_cast<__asan::AsanThreadContext *>(tctx);
+  __asan::AsanThread *asan_thread = atctx->thread;
+
+  // Note ThreadStatusRunning is required because there is a small window where
+  // the thread status switches to `ThreadStatusRunning` but the `arg` pointer
+  // still isn't on the stack yet.
+  if (atctx->status != ThreadStatusCreated &&
+      atctx->status != ThreadStatusRunning)
+    return;
+
+  uptr thread_arg = reinterpret_cast<uptr>(asan_thread->get_arg());
+  if (!thread_arg)
+    return;
+
+  auto ptrsVec = reinterpret_cast<InternalMmapVector<uptr> *>(ptrs);
+  ptrsVec->push_back(thread_arg);
+}
+
 }  // namespace __lsan
 
 // ---------------------- Interface ---------------- {{{1