message: Prevent possible concurrent CBanDB::Write() calls
diff: #include <netaddress.h>
  #include <node/ui_interface.h>
  +#include <sync.h>
  #include <util/system.h>
  #include <util/time.h>
  #include <util/translation.h>
  @@ -39,6 +40,9 @@ BanMan::~BanMan()
  void BanMan::DumpBanlist()
  {
  + static Mutex dump_mutex;
  + LOCK(dump_mutex);
  +
  SweepBanned(); // clean unused entries (if bantime has expired)
  if (!BannedSetIsDirty()) return;
  