[libFuzzer] don't report memory leaks if we are dying due to a timeout (just use _Exit instead of exit in the timeout callback)

llvm-svn: 264237

llvm/lib/Fuzzer/FuzzerLoop.cpp

@@ -164,7 +164,7 @@ void Fuzzer::AlarmCallback() {
       __sanitizer_print_stack_trace();
     Printf("SUMMARY: libFuzzer: timeout\n");
     PrintFinalStats();
-    exit(Options.TimeoutExitCode);
+    _Exit(Options.TimeoutExitCode); // Stop right now.
   }
 }
 

llvm/lib/Fuzzer/test/CMakeLists.txt

@@ -22,6 +22,7 @@ set(Tests
   InitializeTest
   MemcmpTest
   LeakTest
+  LeakTimeoutTest
   NullDerefTest
   NthRunCrashTest
   RepeatedMemcmp

llvm/lib/Fuzzer/test/LeakTimeoutTest.cpp

@@ -0,0 +1,14 @@
+// Test with a leak.
+#include <cstdint>
+#include <cstddef>
+
+static volatile int *Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (!Size) return 0;
+  Sink = new int;
+  Sink = new int;
+  while (Sink) *Sink = 0;  // Infinite loop.
+  return 0;
+}
+

llvm/lib/Fuzzer/test/fuzzer-leak.test

@@ -0,0 +1,9 @@
+RUN: not LLVMFuzzer-LeakTest -runs=10 2>&1 | FileCheck %s --check-prefix=LEAK
+LEAK: ERROR: LeakSanitizer: detected memory leaks
+LEAK-NOT: DEATH:
+
+RUN: not LLVMFuzzer-LeakTimeoutTest -timeout=1 2>&1 | FileCheck %s --check-prefix=LEAK_TIMEOUT
+LEAK_TIMEOUT: ERROR: libFuzzer: timeout after
+LEAK_TIMEOUT-NOT: LeakSanitizer
+
+

llvm/lib/Fuzzer/test/fuzzer.test

@@ -69,10 +69,6 @@ RUN: LLVMFuzzer-SimpleTest %t/SUB1 -runs=0 2>&1 | FileCheck %s --check-prefix=SU
 SUBDIRS: READ   units: 3
 RUN: rm -rf %t/SUB1
 
-RUN: not LLVMFuzzer-LeakTest -runs=10 2>&1 | FileCheck %s --check-prefix=LEAK
-LEAK: ERROR: LeakSanitizer: detected memory leaks
-LEAK-NOT: DEATH:
-
 RUN: mkdir -p %t
 RUN: echo abcd > %t/NthRunCrashTest.in
 RUN: LLVMFuzzer-NthRunCrashTest %t/NthRunCrashTest.in