When disconnecting a bcm203x device we kill and destroy the usb-urb, however,
there might still be a pending work-structure which resubmits the now invalid
urb. To avoid this race condition, we simply set a shutdown-flag and
synchronously kill the worker first.
This also adds a comment to all schedule_work()s, as it is really not clear
that they are used as replacement for short timers (which can be seen in the git
history).
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxxxxxxx>
---
drivers/bluetooth/bcm203x.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/bluetooth/bcm203x.c b/drivers/bluetooth/bcm203x.c
index 8b1b643..6b42732 100644
--- a/drivers/bluetooth/bcm203x.c
+++ b/drivers/bluetooth/bcm203x.c
@@ -24,6 +24,7 @@
#include <linux/module.h>
+#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
@@ -65,6 +66,7 @@ struct bcm203x_data {
unsigned long state;
struct work_struct work;
+ atomic_t shutdown;
struct urb *urb;
unsigned char *buffer;
@@ -97,6 +99,7 @@ static void bcm203x_complete(struct urb *urb)
data->state = BCM203X_SELECT_MEMORY;
+ /* use workqueue to have a small delay */
schedule_work(&data->work);
break;
@@ -155,6 +158,10 @@ static void bcm203x_work(struct work_struct *work)
struct bcm203x_data *data =
container_of(work, struct bcm203x_data, work);
+ smp_rmb();
+ if (atomic_read(&data->shutdown))
+ return;
+
if (usb_submit_urb(data->urb, GFP_ATOMIC) < 0)
BT_ERR("Can't submit URB");
}
@@ -243,6 +250,7 @@ static int bcm203x_probe(struct usb_interface *intf, const struct usb_device_id
usb_set_intfdata(intf, data);
+ /* use workqueue to have a small delay */
schedule_work(&data->work);
return 0;
@@ -254,6 +262,10 @@ static void bcm203x_disconnect(struct usb_interface *intf)
BT_DBG("intf %p", intf);
+ atomic_inc(&data->shutdown);
+ smp_wmb();
+ cancel_work_sync(&data->work);
+
usb_kill_urb(data->urb);
usb_set_intfdata(intf, NULL);
--
1.7.7.1
--
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