[flaky tests] Address LSAN false positives

Some tests, like external_mini_cluster-itest, are now only failing
in ASAN due to leaks. Upon inspection I could only find false
positives among these leaks around thread local variables.

This seems related to this issue:
google/sanitizers#757

The fix is to wrap those specific instances of false positives
with ScopedLeakDisabler so that they don't get reported.

After many tries I was unable to come up with the right incantation
to cause this in dist-tests. Running the highest failing test in
ASAN with stress was not enough to cause this. Somehow this is
more likely in jenkins where these failures are pretty common.

Change-Id: I8c8d9ff83c0cfbc11cab213a25cbd5daa3b25869
Reviewed-on: http://gerrit.cloudera.org:8080/6320
Reviewed-by: David Ribeiro Alves <[email protected]>
Tested-by: Kudu Jenkins

src/kudu/util/kernel_stack_watchdog.cc

@@ -23,6 +23,7 @@
 #include <string>
 
 #include "kudu/util/debug-util.h"
+#include "kudu/util/debug/leakcheck_disabler.h"
 #include "kudu/util/env.h"
 #include "kudu/util/faststring.h"
 #include "kudu/util/flag_tags.h"
@@ -154,6 +155,9 @@ void KernelStackWatchdog::RunThread() {
 }
 
 KernelStackWatchdog::TLS* KernelStackWatchdog::GetTLS() {
+  // Disable leak check. LSAN sometimes gets false positives on thread locals.
+  // See: https://github.com/google/sanitizers/issues/757
+  debug::ScopedLeakCheckDisabler d;
   INIT_STATIC_THREAD_LOCAL(KernelStackWatchdog::TLS, tls_);
   return tls_;
 }

src/kudu/util/thread_restrictions.cc

@@ -18,6 +18,7 @@
 #include <glog/logging.h>
 #include <gperftools/heap-checker.h>
 
+#include "kudu/util/debug/leakcheck_disabler.h"
 #include "kudu/util/thread.h"
 #include "kudu/util/threadlocal.h"
 #include "kudu/util/thread_restrictions.h"
@@ -41,6 +42,9 @@ struct LocalThreadRestrictions {
 };
 
 LocalThreadRestrictions* LoadTLS() {
+  // Disable leak check. LSAN sometimes gets false positives on thread locals.
+  // See: https://github.com/google/sanitizers/issues/757
+  debug::ScopedLeakCheckDisabler d;
   BLOCK_STATIC_THREAD_LOCAL(LocalThreadRestrictions, local_thread_restrictions);
   return local_thread_restrictions;
 }