From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Alan Stern , Don Zickus , "Huang, Adrian (ISS Linux TW)" Subject: [ 04/15] USB: UHCI: fix IRQ race during initialization Date: Thu, 24 Jan 2013 13:18:28 -0800 Message-Id: <20130124211724.989791486@linuxfoundation.org> In-Reply-To: <20130124211723.489089115@linuxfoundation.org> References: <20130124211723.489089115@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit 0f815a0a700bc10547449bde6c106051a035a1b9 upstream. 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: Alan Stern Reported-by: Don Zickus Tested-by: "Huang, Adrian (ISS Linux TW)" Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/uhci-hcd.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/drivers/usb/host/uhci-hcd.c +++ b/drivers/usb/host/uhci-hcd.c @@ -446,6 +446,10 @@ static irqreturn_t uhci_irq(struct usb_h 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, " @@ -454,7 +458,6 @@ static irqreturn_t uhci_irq(struct usb_h 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, " @@ -472,15 +475,15 @@ static irqreturn_t uhci_irq(struct usb_h * 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); } @@ -658,9 +661,9 @@ static int uhci_start(struct usb_hcd *hc */ 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;