[lsan] Add thread_suspend_fail flag

Author: vitalybuka

compiler-rt/lib/lsan/lsan_common.cpp

@@ -702,7 +702,7 @@ static void ReportUnsuspendedThreads(const SuspendedThreadsList &) {}
 
 #  else  // !SANITIZER_FUCHSIA
 
-static void ReportUnsuspendedThreads(
+static bool ReportUnsuspendedThreads(
     const SuspendedThreadsList &suspended_threads) {
   InternalMmapVector<tid_t> threads(suspended_threads.ThreadCount());
   for (uptr i = 0; i < suspended_threads.ThreadCount(); ++i)
@@ -713,13 +713,17 @@ static void ReportUnsuspendedThreads(
   InternalMmapVector<tid_t> unsuspended;
   GetRunningThreadsLocked(&unsuspended);
 
+  bool succeded = true;
   for (auto os_id : unsuspended) {
     uptr i = InternalLowerBound(threads, os_id);
-    if (i >= threads.size() || threads[i] != os_id)
+    if (i >= threads.size() || threads[i] != os_id) {
+      succeded = false;
       Report(
           "Running thread %zu was not suspended. False leaks are possible.\n",
           os_id);
+    }
   }
+  return succeded;
 }
 
 #  endif  // !SANITIZER_FUCHSIA
@@ -729,7 +733,18 @@ static void CheckForLeaksCallback(const SuspendedThreadsList &suspended_threads,
   CheckForLeaksParam *param = reinterpret_cast<CheckForLeaksParam *>(arg);
   CHECK(param);
   CHECK(!param->success);
-  ReportUnsuspendedThreads(suspended_threads);
+  if (!ReportUnsuspendedThreads(suspended_threads)) {
+    switch (flags()->thread_suspend_fail) {
+      case 0:
+        param->success = true;
+        return;
+      case 1:
+        break;
+      case 2:
+        // Will crash on return.
+        return;
+    }
+  }
   ClassifyAllChunks(suspended_threads, &param->frontier, param->caller_tid,
                     param->caller_sp);
   ForEachChunk(CollectLeaksCb, &param->leaks);

compiler-rt/lib/lsan/lsan_flags.inc

@@ -44,3 +44,7 @@ LSAN_FLAG(bool, use_poisoned, false,
 LSAN_FLAG(bool, log_pointers, false, "Debug logging")
 LSAN_FLAG(bool, log_threads, false, "Debug logging")
 LSAN_FLAG(const char *, suppressions, "", "Suppressions file name.")
+LSAN_FLAG(int, thread_suspend_fail, 1,
+          "Behaviour if thread suspendion all thread (0 - "
+          "abandon leak checking, 1 - continue with leak checking (reported "
+          "leaks can be false), 2 - crash (for debugging LSAN)).")