There is a window:
task A task B
spin_lock_irq(&usbhid->inlock); /* Sync with error handler */
usb_set_intfdata(intf, NULL);
spin_unlock_irq(&usbhid->inlock);
usb_kill_urb(usbhid->urbin);
usb_kill_urb(usbhid->urbout);
usb_kill_urb(usbhid->urbctrl);
del_timer_sync(&usbhid->io_retry);
cancel_work_sync(&usbhid->reset_work);
if (!hid->open++) {
res = usb_autopm_get_interface(usbhid->intf);
if (res < 0) {
hid->open--;
return -EIO;
}
}
if (hid_start_in(hid))
if (hid->claimed & HID_CLAIMED_INPUT)
hidinput_disconnect(hid);
in which an open() to an already disconnected device will submit an URB
to an undead device. In case disconnect() was called by an ioctl, this'll
oops. Fix by introducing a reliable flag an checking it in hid_start_in().
Signed-off-by: Oliver Neukum <oneukum@xxxxxxx>
----
--- linux-2.6.25-rc7-vanilla/drivers/hid/usbhid/usbhid.h 2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.25-rc7-work/drivers/hid/usbhid/usbhid.h 2008-03-31 13:45:25.000000000 +0200
@@ -77,6 +77,7 @@
unsigned long stop_retry; /* Time to give up, in jiffies */
unsigned int retry_delay; /* Delay length in ms */
struct work_struct reset_work; /* Task context for resets */
+ char disconnected:1; /* indicates undead device - no use */
};
--- linux-2.6.25-rc7-vanilla/drivers/hid/usbhid/hid-core.c 2008-03-31 15:20:58.000000000 +0200
+++ linux-2.6.25-rc7-work/drivers/hid/usbhid/hid-core.c 2008-03-31 13:45:10.000000000 +0200
@@ -82,6 +82,7 @@
spin_lock_irqsave(&usbhid->inlock, flags);
if (hid->open > 0 && !test_bit(HID_SUSPENDED, &usbhid->iofl) &&
+ !usbhid->disconnected &&
!test_and_set_bit(HID_IN_RUNNING, &usbhid->iofl)) {
rc = usb_submit_urb(usbhid->urbin, GFP_ATOMIC);
if (rc != 0)
@@ -155,7 +156,7 @@
spin_lock_irqsave(&usbhid->inlock, flags);
/* Stop when disconnected */
- if (usb_get_intfdata(usbhid->intf) == NULL)
+ if (usbhid->disconnected)
goto done;
/* If it has been a while since the last error, we'll assume
@@ -932,6 +933,7 @@
spin_lock_irq(&usbhid->inlock); /* Sync with error handler */
usb_set_intfdata(intf, NULL);
+ usbhid->disconnected = 1;
spin_unlock_irq(&usbhid->inlock);
usb_kill_urb(usbhid->urbin);
usb_kill_urb(usbhid->urbout);
--
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