[PATCH] D46650: [lsan] Try to fix test failure due to compiler optimization

[Peter Wu via Phabricator via llvm-commits]

Lekensteyn created this revision.
Lekensteyn added reviewers: m.ostapenko, rengolin, kcc.
Lekensteyn added a project: Sanitizers.
Herald added subscribers: Sanitizers, llvm-commits, kubamracek.

Fix SanitizerCommon-lsan-x86_64-Linux test failure by cleaning the
stack. The issue was only present with optimization enabled, building
the whole test with -O0 did not trigger any issue.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D46650

Files:
  test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc


Index: test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc
===================================================================
--- test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc
+++ test/sanitizer_common/TestCases/Posix/sanitizer_set_death_callback_test.cc
@@ -2,12 +2,6 @@
 
 // REQUIRES: stable-runtime
 
-// For standalone LSan on x86 we have a problem: compiler spills the address
-// of allocated at line 42 memory thus memory block allocated in Leak() function
-// ends up to be classified as reachable despite the fact we zero out 'sink' at
-// the last line of main function. The problem doesn't reproduce with ASan because
-// quarantine prohibits memory block reuse for different allocations.
-// XFAIL: lsan-x86
 // XFAIL: ubsan
 
 #include <sanitizer/common_interface_defs.h>
@@ -34,6 +28,13 @@
   sink = new char[100];  // trigger lsan report.
 }
 
+// Ensure stack memory is erased, otherwise the sink pointer passed to
+// "delete[]" might be left on the stack.
+__attribute__((noinline, optnone))
+void ClearStackMemory(char *dummy_for_x86) {
+  void *stack[100] = {0};
+}
+
 int main(int argc, char **argv) {
   int uninitialized;
   __sanitizer_set_death_callback(Death);
@@ -45,4 +46,5 @@
   global = sink[0];  // use-after-free: trigger asan/tsan report.
   Leak();
   sink = 0;
+  ClearStackMemory(0);
 }


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