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USB: fix race in HCD removal
This patch (as865) fixes a race in the HCD removal code discovered by Milan Plzik. Arrival of an interrupt after the root hub was unregistered could cause the root-hub status timer to start up, even after it was supposed to have been shut down. The problem is fixed by moving the del_timer_sync() call to after the HCD's stop() method, at which time IRQ generation should be disabled. Cc: Milan Plzik <milan.plzik@gmail.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -544,6 +544,8 @@ void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
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unsigned long flags;
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unsigned long flags;
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char buffer[4]; /* Any root hubs with > 31 ports? */
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char buffer[4]; /* Any root hubs with > 31 ports? */
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if (unlikely(!hcd->rh_registered))
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return;
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if (!hcd->uses_new_polling && !hcd->status_urb)
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if (!hcd->uses_new_polling && !hcd->status_urb)
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return;
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return;
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@ -1670,12 +1672,12 @@ void usb_remove_hcd(struct usb_hcd *hcd)
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usb_disconnect(&hcd->self.root_hub);
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usb_disconnect(&hcd->self.root_hub);
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mutex_unlock(&usb_bus_list_lock);
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mutex_unlock(&usb_bus_list_lock);
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hcd->poll_rh = 0;
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del_timer_sync(&hcd->rh_timer);
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hcd->driver->stop(hcd);
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hcd->driver->stop(hcd);
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hcd->state = HC_STATE_HALT;
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hcd->state = HC_STATE_HALT;
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hcd->poll_rh = 0;
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del_timer_sync(&hcd->rh_timer);
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if (hcd->irq >= 0)
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if (hcd->irq >= 0)
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free_irq(hcd->irq, hcd);
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free_irq(hcd->irq, hcd);
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usb_deregister_bus(&hcd->self);
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usb_deregister_bus(&hcd->self);
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