What steps will reproduce the problem?
1. export ASAN_OPTIONS=print_stats=1
2. Run programs under Linux. When generating error reports, asan stucks.

What is the expected output? What do you see instead?
Generates error reports and exit the program.

What version of the product are you using? On what operating system?
I run under GCC 4.9.
I check http://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/sanitizer_common and
find it not fixed.

Please provide any additional information below.
In asan_report.cc
class ScopedInErrorReport {
 public:
  ScopedInErrorReport() {
    ...

    ASAN_ON_ERROR();
    // Make sure the registry and sanitizer report mutexes are locked while
    // we're printing an error report.
    // We can lock them only here to avoid self-deadlock in case of
    // recursive reports.
    asanThreadRegistry().Lock(); //@@@@@lock once
    CommonSanitizerReportMutex.Lock();
    reporting_thread_tid = GetCurrentTidOrInvalid();
    Printf("===================================================="
           "=============\n");
  }
  // Destructor is NORETURN, as functions that report errors are.
  NORETURN ~ScopedInErrorReport() {
    // Make sure the current thread is announced.
    DescribeThread(GetCurrentThread());
    // Print memory stats.
    if (flags()->print_stats)
      __asan_print_accumulated_stats(); //@@@@@lock twice
    if (error_report_callback) {
      error_report_callback(error_message_buffer);
    }
    Report("ABORTING\n");
    Die();
  }
};

Since __asan_print_accumulated_stats() indirectly calls GetAccumulatedStats(&stats),
and
static void GetAccumulatedStats(AsanStats *stats) {
  stats->Clear();
  {
    ThreadRegistryLock l(&asanThreadRegistry()); //the twice lock
    asanThreadRegistry()
        .RunCallbackForEachThreadLocked(MergeThreadStats, stats);
  }
  ...
}