From 6dd433e6cf2475ce8abec1b467720858c24450eb Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Tue, 6 Aug 2013 14:22:59 +0200 Subject: [PATCH] USB: cdc-wdm: fix race between interrupt handler and tasklet Both could want to submit the same URB. Some checks of the flag intended to prevent that were missing. Signed-off-by: Oliver Neukum CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-wdm.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 8a230f0ef77c..d3318a0df8ee 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -209,6 +209,7 @@ skip_error: static void wdm_int_callback(struct urb *urb) { int rv = 0; + int responding; int status = urb->status; struct wdm_device *desc; struct usb_cdc_notification *dr; @@ -262,8 +263,8 @@ static void wdm_int_callback(struct urb *urb) spin_lock(&desc->iuspin); clear_bit(WDM_READ, &desc->flags); - set_bit(WDM_RESPONDING, &desc->flags); - if (!test_bit(WDM_DISCONNECTING, &desc->flags) + responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); + if (!responding && !test_bit(WDM_DISCONNECTING, &desc->flags) && !test_bit(WDM_SUSPENDING, &desc->flags)) { rv = usb_submit_urb(desc->response, GFP_ATOMIC); dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d", @@ -685,16 +686,20 @@ static void wdm_rxwork(struct work_struct *work) { struct wdm_device *desc = container_of(work, struct wdm_device, rxwork); unsigned long flags; - int rv; + int rv = 0; + int responding; spin_lock_irqsave(&desc->iuspin, flags); if (test_bit(WDM_DISCONNECTING, &desc->flags)) { spin_unlock_irqrestore(&desc->iuspin, flags); } else { + responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); spin_unlock_irqrestore(&desc->iuspin, flags); - rv = usb_submit_urb(desc->response, GFP_KERNEL); + if (!responding) + rv = usb_submit_urb(desc->response, GFP_KERNEL); if (rv < 0 && rv != -EPERM) { spin_lock_irqsave(&desc->iuspin, flags); + clear_bit(WDM_RESPONDING, &desc->flags); if (!test_bit(WDM_DISCONNECTING, &desc->flags)) schedule_work(&desc->rxwork); spin_unlock_irqrestore(&desc->iuspin, flags); -- 2.25.1