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authorOliver Neukum <oneukum@suse.de>2013-08-06 14:22:59 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-12 15:41:07 -0700
commit6dd433e6cf2475ce8abec1b467720858c24450eb (patch)
treefc3359d4bd68a1216835b3ca12221f8632ed602b /drivers/usb/class/cdc-wdm.c
parente9a088fae5e4f9be729f3f419627abc3886b09de (diff)
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 <oneukum@suse.de> CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class/cdc-wdm.c')
-rw-r--r--drivers/usb/class/cdc-wdm.c13
1 files 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);