[ Resend ... Greg, this one should likely merge to 2.6.18, and I don't
think I saw any other fix for this in your current patchset ]
This fixes a locking problem reported by the new lock debug tools which, while
very cryptic, gave Alan Stern enough info to finger the problem: a routine
wrongly enabled IRQs on exit, by using the wrong locking/irq primitives.
This patch switches back to the primitives which save/restore IRQ flags.
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
Index: g26/drivers/usb/core/hcd.c
===================================================================
--- g26.orig/drivers/usb/core/hcd.c 2006-07-03 10:45:18.000000000 -0700
+++ g26/drivers/usb/core/hcd.c 2006-07-25 14:00:14.000000000 -0700
@@ -632,31 +632,33 @@ static int rh_urb_enqueue (struct usb_hc
/*-------------------------------------------------------------------------*/
-/* Asynchronous unlinks of root-hub control URBs are legal, but they
- * don't do anything. Status URB unlinks must be made in process context
- * with interrupts enabled.
+/* Root hub control URBs are synchronous, so unlinking would be pointless.
+ * Status URBs may not be unlinked from interrupts (del_timer_sync rule).
*/
static int usb_rh_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
{
+ unsigned long flags;
+
if (usb_pipeendpoint(urb->pipe) == 0) { /* Control URB */
if (in_interrupt())
return 0; /* nothing to do */
- spin_lock_irq(&urb->lock); /* from usb_kill_urb */
- ++urb->reject;
- spin_unlock_irq(&urb->lock);
+ spin_lock_irqsave(&urb->lock, flags);
+ ++urb->reject; /* like usb_kill_urb */
+ spin_unlock_irqrestore(&urb->lock, flags);
wait_event(usb_kill_urb_queue,
atomic_read(&urb->use_count) == 0);
- spin_lock_irq(&urb->lock);
+ spin_lock_irqsave(&urb->lock, flags);
--urb->reject;
- spin_unlock_irq(&urb->lock);
+ spin_unlock_irqrestore(&urb->lock, flags);
} else { /* Status URB */
if (!hcd->uses_new_polling)
del_timer_sync (&hcd->rh_timer);
- local_irq_disable ();
+
+ local_irq_save (flags);
spin_lock (&hcd_root_hub_lock);
if (urb == hcd->status_urb) {
hcd->status_urb = NULL;
@@ -666,7 +668,7 @@ static int usb_rh_urb_dequeue (struct us
spin_unlock (&hcd_root_hub_lock);
if (urb)
usb_hcd_giveback_urb (hcd, urb, NULL);
- local_irq_enable ();
+ local_irq_restore (flags);
}
return 0;
-------------------------------------------------------------------------
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