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USB: cdc-wdm: fix race between interrupt handler and tasklet

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Both could want to submit the same URB. Some checks of the flag
intended to prevent that were missing.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
CC: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oliver Neukum 2013-08-06 14:22:59 +02:00 committed by Greg Kroah-Hartman
parent e9a088fae5
commit 6dd433e6cf
1 changed files with 9 additions and 4 deletions
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13
drivers/usb/class/cdc-wdm.c
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@ -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);