Cache problem after upgrading

Hi, Kamlesh Patidar

I changed the cache.inc file.

function cache_set($cid, $table = 'cache', $data, $expire = CACHE_PERMANENT, $headers = NULL) {

  + $serialized = 0;
  + if (is_object($data) || is_array($data)) {
  +   $data = serialize($data);
  +  $serialized = 1;
  + }

  db_lock_table($table);
  db_query("UPDATE {". $table. "} SET data = %b, created = %d, expire = %d, headers = '%s', serialized = %d WHERE cid = '%s'", $data, time(), $expire, $headers, $serialized, $cid);
  if (!db_affected_rows()) {
    @db_query("INSERT INTO {". $table. "} (cid, data, created, expire, headers, serialized) VALUES ('%s', %b, %d, %d, '%s', '%d')", $cid, $data, time(), $expire, $headers, $serialized);
  }
  db_unlock_tables();
}

function cache_get($key, $table = 'cache') {
  global $user;

  // Garbage collection necessary when enforcing a minimum cache lifetime
  $cache_flush = variable_get('cache_flush', 0);
  if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= time())) {
    // Reset the variable immediately to prevent a meltdown in heavy load situations.
    variable_set('cache_flush', 0);
    // Time to flush old cache data
    db_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire <= %d", CACHE_PERMANENT, $cache_flush);
  }

  $cache = db_fetch_object(db_query("SELECT data, created, headers, expire, serialized FROM {". $table ."} WHERE cid = '%s'", $key));
  if (isset($cache->data)) {
    // If the data is permanent or we're not enforcing a minimum cache lifetime
    // always return the cached data.
    if ($cache->expire == CACHE_PERMANENT || !variable_get('cache_lifetime', 0)) {
      $cache->data = db_decode_blob($cache->data);

      + if ($cache->serialized) {
      + $cache->data = unserialize($cache->data);
      + }

    }
    // If enforcing a minimum cache lifetime, validate that the data is
    // currently valid for this user before we return it by making sure the
    // cache entry was created before the timestamp in the current session's
    // cache timer. The cache variable is loaded into the $user object by
    // sess_read() in session.inc.
    else {
      if ($user->cache > $cache->created) {
        // This cache data is too old and thus not valid for us, ignore it.
        return 0;
      }
      else {
        $cache->data = db_decode_blob($cache->data);
      }
    }
    return $cache;
  }
  return 0;
}

All my problems were caused by that the serialize and unserialize functions were missed in some place, what I did was add them back.
I hope this can help you!