What to do with: "Cron has been running for more than an hour and is most likely stuck."

i managed to fix it by hacking common.inc. Line 1986 - get 'variable_get()' call to get the value of the semaphore variable - it was returning, according to the log file, the value '1187524663'.

how in the world could that happen?

so, to fix, i forced the '$semaphore' variable to FALSE (I had already tried deleting all 'cron%' entries from the db, and that did not work), ran the cron successfully through the admin menus, then removed my hacked code and now all is fine. i checked the return value of Semaphore now, and it comes back blank - when seems to be essentially correct, but i'm not too sure of that. confused about the max time of one hour and such.

the other unknowns in this mix are that i had just installed the 'Syndication' module and turned off the normal/built-in Node syndication. I also added a new feed for the News Aggregator - this new feed seemed to be giving some problems.

Still, getting that return value was really weird. And scary. The 'variable_get()' function seems to be a core part of Drupal...

/**
 * Executes a cron run when called
 * @return
 * Returns TRUE if ran successfully
 */
function drupal_cron_run() {
  // If not in 'safe mode', increase the maximum execution time:
  if (!ini_get('safe_mode')) {
    set_time_limit(240);
  }

  // Fetch the cron semaphore
  //$semaphore = variable_get('cron_semaphore', FALSE);
  $semaphore = FALSE;

  if ($semaphore) {
    if (time() - $semaphore > 3600) {
      // Either cron has been running for more than an hour or the semaphore
      // was not reset due to a database error.
      watchdog('cron', t('Cron has been running for more than an hour and is most likely stuck.'), WATCHDOG_ERROR);

      // Release cron semaphore
      variable_del('cron_semaphore');
    }
    else {
      // Cron is still running normally.
      watchdog('cron', t('What in the world is going on here? The value of $semaphore is \''.$semaphore.'\'.'), WATCHDOG_WARNING);
      watchdog('cron', t('Attempting to re-run cron while it is already running.'), WATCHDOG_WARNING);
    }
  }
...