| From | Ben Hutchings <> | Date | Mon, 21 Oct 2013 09:46:28 +0100 | Subject | [PATCH 3.2 023/149] USB: cdc-wdm: fix race between interrupt handler and tasklet |
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3.2.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum <oneukum@suse.de>
commit 6dd433e6cf2475ce8abec1b467720858c24450eb upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/usb/class/cdc-wdm.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
--- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -187,6 +187,7 @@ 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_ctrlrequest *req; @@ -260,8 +261,8 @@ static void wdm_int_callback(struct urb desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; 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", @@ -658,16 +659,20 @@ static void wdm_rxwork(struct work_struc { 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);
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