From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754713Ab3BCPIx (ORCPT ); Sun, 3 Feb 2013 10:08:53 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34421 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751601Ab3BCO5B (ORCPT ); Sun, 3 Feb 2013 09:57:01 -0500 Message-Id: <20130203144650.893892587@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 03 Feb 2013 15:48:01 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, Alan Stern , Don Zickus , "Huang, Adrian (ISS Linux TW)" , Greg Kroah-Hartman Subject: [ 077/128] USB: UHCI: fix IRQ race during initialization In-Reply-To: <20130203144644.035172954@decadent.org.uk> X-SA-Exim-Connect-IP: 151.216.67.5 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-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 Signed-off-by: Ben Hutchings --- drivers/usb/host/uhci-hcd.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c index 4b9e9ab..4f64d24 100644 --- a/drivers/usb/host/uhci-hcd.c +++ b/drivers/usb/host/uhci-hcd.c @@ -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;