title: Not able to mount debugfs on ath9k driver
body: <p>I am mounting debugfs on ath9k driver. I am following the procedure mentioned in ath9k's manual (<a href="https://wireless.wiki.kernel.org/en/users/drivers/ath9k/debug" rel="nofollow">https://wireless.wiki.kernel.org/en/users/drivers/ath9k/debug</a>). </p>
  
  <p>The following command was used for mounting after CONFIG_ATH_DEBUG option was enabled:
  mount -t debugfs debugfs /sys/kernel/debug/</p>
  
  <p>I am getting following error after executing the above command:</p>
  
  <p>mount: debugfs already mounted or /sys/kernel/debug/ busy</p>
  
  <p>mount: according to mtab, none is already mounted on /sys/kernel/debug</p>
  
  <p>I am not able to figure out what might be causing this error, any help would be greatly appreciated.</p>