[fuzzer] Fix threaded stack printing and nested mallocs

Summary: Nested mallocs are possible with internal symbolizer.

Reviewers: kcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39397

llvm-svn: 317034

1 files changed, 22 insertions, 0 deletions

diff --git a/compiler-rt/test/fuzzer/TraceMallocThreadedTest.cpp b/compiler-rt/test/fuzzer/TraceMallocThreadedTest.cpp
new file mode 100644
index 00000000000..5603af344cb
--- /dev/null
+++ b/compiler-rt/test/fuzzer/TraceMallocThreadedTest.cpp
@@ -0,0 +1,22 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Check that allocation tracing from different threads does not cause
+// interleaving of stack traces.
+#include <assert.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <thread>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  auto C = [&] {
+    volatile void *a = malloc(5639);
+    free((void *)a);
+  };
+  std::thread T[] = {std::thread(C), std::thread(C), std::thread(C),
+                     std::thread(C), std::thread(C), std::thread(C)};
+  for (auto &X : T)
+    X.join();
+  return 0;
+}