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Commit 0f815a0a authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: UHCI: fix IRQ race during initialization 



This patch (as1644) fixes a race that occurs during startup in
uhci-hcd.  If the IRQ line is shared with other devices, it's possible
for the handler routine to be called before the data structures are
fully initialized.

The problem is fixed by adding a check to the IRQ handler routine.  If
the initialization hasn't finished yet, the routine will return
immediately.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-by: default avatarDon Zickus <dzickus@redhat.com>
Tested-by: default avatar"Huang, Adrian (ISS Linux TW)" <adrian.huang@hp.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ad2e6329

drivers/usb/host/uhci-hcd.c

+9 −6
Original line number Diff line number Diff line
@@ -447,6 +447,10 @@ static irqreturn_t uhci_irq(struct usb_hcd *hcd) 
		return IRQ_NONE;

	uhci_writew(uhci, status, USBSTS);		/* Clear it */



	spin_lock(&uhci->lock);

	if (unlikely(!uhci->is_initialized))	/* not yet configured */

		goto done;



	if (status & ~(USBSTS_USBINT | USBSTS_ERROR | USBSTS_RD)) {

		if (status & USBSTS_HSE)

			dev_err(uhci_dev(uhci), "host system error, "
@@ -455,7 +459,6 @@ static irqreturn_t uhci_irq(struct usb_hcd *hcd) 
			dev_err(uhci_dev(uhci), "host controller process "

					"error, something bad happened!\n");

		if (status & USBSTS_HCH) {

			spin_lock(&uhci->lock);

			if (uhci->rh_state >= UHCI_RH_RUNNING) {

				dev_err(uhci_dev(uhci),

					"host controller halted, "
@@ -473,15 +476,15 @@ static irqreturn_t uhci_irq(struct usb_hcd *hcd) 
				 * pending unlinks */

				mod_timer(&hcd->rh_timer, jiffies);

			}

			spin_unlock(&uhci->lock);

		}

	}



	if (status & USBSTS_RD)

	if (status & USBSTS_RD) {

		spin_unlock(&uhci->lock);

		usb_hcd_poll_rh_status(hcd);

	else {

		spin_lock(&uhci->lock);

	} else {

		uhci_scan_schedule(uhci);

 done:

		spin_unlock(&uhci->lock);

	}
@@ -662,9 +665,9 @@ static int uhci_start(struct usb_hcd *hcd) 
	 */

	mb();



	spin_lock_irq(&uhci->lock);

	configure_hc(uhci);

	uhci->is_initialized = 1;

	spin_lock_irq(&uhci->lock);

	start_rh(uhci);

	spin_unlock_irq(&uhci->lock);

	return 0;