On Wed, Nov 04, 2009 at 12:00:25AM -0600, Larry Finger wrote: > As reported by Rick Farina (sidhayn@xxxxxxxxx), removing the RTL8187 USB > stick, or unloading the driver rtl8187 using rmmod will cause a kernel oops. > There are at least two forms of the failure, (1) BUG: Scheduling while atomic, > and (2) a fatal kernel page fault. This problem is reported in Bugzilla #14539. > > This problem does not occur for kernel 2.6.31, but does for 2.6.32-rc2, thus > it is technically a regression; however, bisection did not locate any faulty > patch. The fix was found by comparing the faulty code in rtl8187 with p54usb. > My interpretation is that the handling of work queues in mac80211 changed > enough to the LEDs to be unregistered before tasks on the work queues are > cancelled. Previously, these actions could be done in either order. > > Signed-off-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx> > Reported-and-tested by: Rick Farina <sidhayn@xxxxxxxxx> > --- > > John, > > This is 2.6.32 material. Sorry to take so long to get a patch, but it was > difficult for me to locate the problem. Fortunately, I had the postings of the > two flame wars to amuse me while all the kernel compilations were happening. > > Larry > --- > > Index: wireless-testing/drivers/net/wireless/rtl818x/rtl8187_leds.c > =================================================================== > --- wireless-testing.orig/drivers/net/wireless/rtl818x/rtl8187_leds.c > +++ wireless-testing/drivers/net/wireless/rtl818x/rtl8187_leds.c > @@ -210,10 +210,10 @@ void rtl8187_leds_exit(struct ieee80211_ > > /* turn the LED off before exiting */ > ieee80211_queue_delayed_work(dev, &priv->led_off, 0); > - cancel_delayed_work_sync(&priv->led_off); > - cancel_delayed_work_sync(&priv->led_on); > rtl8187_unregister_led(&priv->led_rx); > rtl8187_unregister_led(&priv->led_tx); > + cancel_delayed_work_sync(&priv->led_off); > + cancel_delayed_work_sync(&priv->led_on); > } > #endif /* def CONFIG_RTL8187_LED */ > This seems like a band-aid. If anything, the original order would seem to make more sense. Do you have a link to the original backtrace? I don't see one in the bugzilla entry. Thanks, John -- John W. Linville Someday the world will need a hero, and you linville@xxxxxxxxxxxxx might be all we have. Be ready. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
