[msan] Unpoison all TLS shadow when leaving a signal handler.

llvm-svn: 189343

1 files changed, 71 insertions, 0 deletions

diff --git a/compiler-rt/lib/msan/lit_tests/signal_stress_test.cc b/compiler-rt/lib/msan/lit_tests/signal_stress_test.cc
new file mode 100644
index 00000000000..e632cde35fa
--- /dev/null
+++ b/compiler-rt/lib/msan/lit_tests/signal_stress_test.cc
@@ -0,0 +1,71 @@
+// RUN: %clangxx_msan -O0 %s -o %t && %t
+
+// Test that va_arg shadow from a signal handler does not leak outside.
+
+#include <signal.h>
+#include <stdarg.h>
+#include <sanitizer/msan_interface.h>
+#include <assert.h>
+#include <sys/time.h>
+#include <stdio.h>
+
+const int kArgCnt = 20;
+const int kSigCnt = 100;
+
+volatile int z;
+
+void f(bool poisoned, ...) {
+  va_list vl;
+  va_start(vl, poisoned);
+  for (int i = 0; i < kArgCnt; ++i) {
+    void *p = va_arg(vl, void *);
+    if (poisoned)
+      assert(__msan_test_shadow(&p, sizeof(p)) == 0);
+    else 
+      assert(__msan_test_shadow(&p, sizeof(p)) == -1);
+  }
+  va_end(vl);
+}
+
+int sigcnt;
+
+void SignalHandler(int signo) {
+  assert(signo == SIGPROF);
+  void *p;
+  void ** volatile q = &p;
+  f(true,
+      *q, *q, *q, *q, *q,
+      *q, *q, *q, *q, *q,
+      *q, *q, *q, *q, *q,
+      *q, *q, *q, *q, *q,
+      *q, *q, *q, *q, *q);
+  ++sigcnt;
+}
+
+int main() {
+  signal(SIGPROF, SignalHandler);
+
+  itimerval itv;
+  itv.it_interval.tv_sec = 0;
+  itv.it_interval.tv_usec = 100;
+  itv.it_value.tv_sec = 0;
+  itv.it_value.tv_usec = 100;
+  setitimer(ITIMER_PROF, &itv, NULL);
+
+  do {
+    f(false,
+        0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0);
+  } while (sigcnt < kSigCnt);
+
+  itv.it_interval.tv_sec = 0;
+  itv.it_interval.tv_usec = 0;
+  itv.it_value.tv_sec = 0;
+  itv.it_value.tv_usec = 0;
+  setitimer(ITIMER_PROF, &itv, NULL);
+
+  signal(SIGPROF, SIG_DFL);
+  return 0;
+}