[sanitizer] Fix asserts in asan and tsan in pthread interceptors.

compiler-rt/lib/sanitizer_common/sanitizer_flags.inc

@@ -279,3 +279,6 @@ COMMON_FLAG(bool, test_only_replace_dlopen_main_program, false,
 COMMON_FLAG(bool, enable_symbolizer_markup, SANITIZER_FUCHSIA,
             "Use sanitizer symbolizer markup, available on Linux "
             "and always set true for Fuchsia.")
+
+COMMON_FLAG(bool, detect_invalid_join, true,
+            "If set, check invalid joins of threads.")

compiler-rt/lib/sanitizer_common/sanitizer_thread_arg_retval.cpp

@@ -23,6 +23,9 @@ void ThreadArgRetval::CreateLocked(uptr thread, bool detached,
   Data& t = data_[thread];
   t = {};
   t.gen = gen_++;
+  static_assert(sizeof(gen_) == sizeof(u32) && kInvalidGen == UINT32_MAX);
+  if (gen_ == kInvalidGen)
+    gen_ = 0;
   t.detached = detached;
   t.args = args;
 }
@@ -53,16 +56,28 @@ void ThreadArgRetval::Finish(uptr thread, void* retval) {
 u32 ThreadArgRetval::BeforeJoin(uptr thread) const {
   __sanitizer::Lock lock(&mtx_);
   auto t = data_.find(thread);
-  CHECK(t);
-  CHECK(!t->second.detached);
-  return t->second.gen;
+  if (t && !t->second.detached) {
+    return t->second.gen;
+  }
+  if (!common_flags()->detect_invalid_join)
+    return kInvalidGen;
+  const char* reason = "unknown";
+  if (!t) {
+    reason = "already joined";
+  } else if (t->second.detached) {
+    reason = "detached";
+  }
+  Report("ERROR: %s: Joining %s thread, aborting.\n", SanitizerToolName,
+         reason);
+  Die();
 }
 
 void ThreadArgRetval::AfterJoin(uptr thread, u32 gen) {
   __sanitizer::Lock lock(&mtx_);
   auto t = data_.find(thread);
   if (!t || gen != t->second.gen) {
-    // Thread was reused and erased by any other event.
+    // Thread was reused and erased by any other event, or we had an invalid
+    // join.
     return;
   }
   CHECK(!t->second.detached);

compiler-rt/lib/sanitizer_common/sanitizer_thread_arg_retval.h

@@ -93,6 +93,7 @@ class SANITIZER_MUTEX ThreadArgRetval {
   // will keep pointers alive forever, missing leaks caused by cancelation.
 
  private:
+  static const u32 kInvalidGen = UINT32_MAX;
   struct Data {
     Args args;
     u32 gen;  // Avoid collision if thread id re-used.

compiler-rt/test/sanitizer_common/TestCases/Linux/pthread_join.cpp

@@ -1,13 +1,14 @@
 // RUN: %clangxx -pthread %s -o %t
-// RUN: %run %t 0
+// RUN: %env_tool_opts=detect_invalid_join=false %run %t 0
 
 // FIXME: Crashes on some bots in pthread_exit.
-// RUN: %run %t %if tsan %{ 0 %} %else %{ 1 %}
+// RUN: %env_tool_opts=detect_invalid_join=false %run %t %if tsan %{ 0 %} %else %{ 1 %}
 
 // REQUIRES: glibc
 
 #include <assert.h>
 #include <ctime>
+#include <errno.h>
 #include <pthread.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -24,6 +25,7 @@ static void *fn(void *args) {
 
 int main(int argc, char **argv) {
   use_exit = atoi(argv[1]);
+  bool check_invalid_join = !use_exit;
   pthread_t thread[5];
   assert(!pthread_create(&thread[0], nullptr, fn, (void *)1000));
   assert(!pthread_create(&thread[1], nullptr, fn, (void *)1001));
@@ -42,6 +44,8 @@ int main(int argc, char **argv) {
     while (pthread_tryjoin_np(thread[1], &res))
       sleep(1);
     assert(~(uintptr_t)res == 1001);
+    assert(check_invalid_join ||
+           (pthread_tryjoin_np(thread[1], &res) == EBUSY));
   }
 
   {
@@ -50,12 +54,15 @@ int main(int argc, char **argv) {
     while (pthread_timedjoin_np(thread[2], &res, &tm))
       sleep(1);
     assert(~(uintptr_t)res == 1002);
+    assert(check_invalid_join ||
+           (pthread_timedjoin_np(thread[2], &res, &tm) == ESRCH));
   }
 
   {
     void *res;
     assert(!pthread_join(thread[3], &res));
     assert(~(uintptr_t)res == 1003);
+    assert(check_invalid_join || (pthread_join(thread[3], &res) == ESRCH));
   }
 
   return 0;

compiler-rt/test/sanitizer_common/TestCases/Linux/pthread_join_invalid.cpp

@@ -0,0 +1,47 @@
+// RUN: %clangxx -pthread %s -o %t
+
+// RUN: %env_tool_opts=detect_invalid_join=true not %run %t 0 2>&1 | FileCheck %s
+// RUN: %env_tool_opts=detect_invalid_join=true not %run %t 1 2>&1 | FileCheck %s
+// RUN: %env_tool_opts=detect_invalid_join=true not %run %t 2 2>&1 | FileCheck %s
+// RUN: %env_tool_opts=detect_invalid_join=true not %run %t 3 2>&1 | FileCheck %s --check-prefix=DETACH
+
+// REQUIRES: glibc && (asan || hwasan || lsan)
+
+#include <assert.h>
+#include <ctime>
+#include <errno.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static void *fn(void *args) {
+  sleep(1);
+  return nullptr;
+}
+
+int main(int argc, char **argv) {
+  int n = atoi(argv[1]);
+  pthread_t thread;
+  assert(!pthread_create(&thread, nullptr, fn, nullptr));
+  void *res;
+  if (n == 0) {
+    while (pthread_tryjoin_np(thread, &res))
+      sleep(1);
+    pthread_tryjoin_np(thread, &res);
+  } else if (n == 1) {
+    timespec tm = {0, 1};
+    while (pthread_timedjoin_np(thread, &res, &tm))
+      sleep(1);
+    pthread_timedjoin_np(thread, &res, &tm);
+  } else if (n == 2) {
+    assert(!pthread_join(thread, &res));
+    pthread_join(thread, &res);
+  } else if (n == 3) {
+    assert(!pthread_detach(thread));
+    pthread_join(thread, &res);
+  }
+  // CHECK: Joining already joined thread
+  // DETACH: Joining detached thread
+  return 0;
+}