-stable review patch. If anyone has any objections, please let us know.
---------------------
From: Simon Arlott <[email protected]>
As part of the device initialisation cxacru_atm_start starts
a rearming status polling task, which is cancelled in
cxacru_unbind. Failure to ever start the task means an
infinite loop occurs trying to cancel it.
Possible reasons for not starting the polling task:
* Firmware files missing
* Device initialisation fails
* User unplugs device or unloads module
Effect:
* Infinite loop in khubd trying to add/remove the device (or rmmod if timed right)
Signed-off-by: Simon Arlott <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
Fixed for 2.6.22 by 6a02c996bce297a782432e29c69268356e97fadd.
drivers/usb/atm/cxacru.c | 40 ++++++++++++++++++++++++++++++++++++----
1 file changed, 36 insertions(+), 4 deletions(-)
--- linux-2.6.21.1.orig/drivers/usb/atm/cxacru.c
+++ linux-2.6.21.1/drivers/usb/atm/cxacru.c
@@ -146,6 +146,12 @@ enum cxacru_info_idx {
CXINF_MAX = 0x1c,
};
+enum poll_state {
+ CX_INIT,
+ CX_POLLING,
+ CX_ABORT
+};
+
struct cxacru_modem_type {
u32 pll_f_clk;
u32 pll_b_clk;
@@ -159,6 +165,8 @@ struct cxacru_data {
int line_status;
struct delayed_work poll_work;
+ struct mutex poll_state_serialize;
+ enum poll_state poll_state;
/* contol handles */
struct mutex cm_serialize;
@@ -356,7 +364,7 @@ static int cxacru_atm_start(struct usbat
/*
struct atm_dev *atm_dev = usbatm_instance->atm_dev;
*/
- int ret;
+ int ret, start_polling = 1;
dbg("cxacru_atm_start");
@@ -376,7 +384,15 @@ static int cxacru_atm_start(struct usbat
}
/* Start status polling */
- cxacru_poll_status(&instance->poll_work.work);
+ mutex_lock(&instance->poll_state_serialize);
+ if (instance->poll_state == CX_INIT)
+ instance->poll_state = CX_POLLING;
+ else /* poll_state == CX_ABORT */
+ start_polling = 0;
+ mutex_unlock(&instance->poll_state_serialize);
+
+ if (start_polling)
+ cxacru_poll_status(&instance->poll_work.work);
return 0;
}
@@ -685,6 +701,9 @@ static int cxacru_bind(struct usbatm_dat
instance->usbatm = usbatm_instance;
instance->modem_type = (struct cxacru_modem_type *) id->driver_info;
+ mutex_init(&instance->poll_state_serialize);
+ instance->poll_state = CX_INIT;
+
instance->rcv_buf = (u8 *) __get_free_page(GFP_KERNEL);
if (!instance->rcv_buf) {
dbg("cxacru_bind: no memory for rcv_buf");
@@ -744,6 +763,7 @@ static void cxacru_unbind(struct usbatm_
struct usb_interface *intf)
{
struct cxacru_data *instance = usbatm_instance->driver_data;
+ int stop_polling = 1;
dbg("cxacru_unbind entered");
@@ -752,8 +772,20 @@ static void cxacru_unbind(struct usbatm_
return;
}
- while (!cancel_delayed_work(&instance->poll_work))
- flush_scheduled_work();
+ mutex_lock(&instance->poll_state_serialize);
+ if (instance->poll_state != CX_POLLING) {
+ /* Polling hasn't started yet and with
+ * the mutex locked it can be prevented
+ * from starting.
+ */
+ instance->poll_state = CX_ABORT;
+ stop_polling = 0;
+ }
+ mutex_unlock(&instance->poll_state_serialize);
+
+ if (stop_polling)
+ while (!cancel_delayed_work(&instance->poll_work))
+ flush_scheduled_work();
usb_kill_urb(instance->snd_urb);
usb_kill_urb(instance->rcv_urb);
--