[PATCH] D52091: [winasan] Unpoison the stack in NtTerminateThread

[David Major via Phabricator via llvm-commits]

dmajor created this revision.
dmajor added a reviewer: rnk.
Herald added subscribers: Sanitizers, llvm-commits, kubamracek.

In long-running builds we've seen some ASan complaints during thread creation that we suspect are due to leftover poisoning from previous threads whose stacks occupied that memory. This patch adds a hook that unpoisons the stack just before the NtTerminateThread syscall.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D52091

Files:
  lib/asan/asan_win.cc


Index: lib/asan/asan_win.cc
===================================================================
--- lib/asan/asan_win.cc
+++ lib/asan/asan_win.cc
@@ -154,14 +154,24 @@
                             asan_thread_start, t, thr_flags, tid);
 }
 
+INTERCEPTOR_WINAPI(void, NtTerminateThread, void* rcx) {
+  // Unpoison the terminating thread's stack because the memory may be re-used.
+  NT_TIB* pTib = reinterpret_cast<NT_TIB*>(NtCurrentTeb());
+  uptr stackSize = (uptr)pTib->StackBase - (uptr)pTib->StackLimit;
+  __asan_unpoison_memory_region(pTib->StackLimit, stackSize);
+  return REAL(NtTerminateThread(rcx));
+}
+
 // }}}
 
 namespace __asan {
 
 void InitializePlatformInterceptors() {
   ASAN_INTERCEPT_FUNC(CreateThread);
   ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
-
+  CHECK(::__interception::OverrideFunction("NtTerminateThread",             
+                                           (uptr)WRAP(NtTerminateThread),
+                                           (uptr *)&REAL(NtTerminateThread)));
 #ifdef _WIN64
   ASAN_INTERCEPT_FUNC(__C_specific_handler);
 #else


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