The URB complete handler may be called by usb_unlink_urb directly,
so deadlock will be triggered in __usbhid_submit_report since
usbhid->lock is to be acquired in ctrl/out URB complete handler
but it is hold before calling usb_unlink_urb.
This patch avoids the deadlock by releasing the lock before
calling usb_unlink_urb.
CC: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
---
drivers/hid/usbhid/hid-core.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index aa1c503..b5d07da 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -543,11 +543,13 @@ static void __usbhid_submit_report(struct hid_device *hid, struct hid_report *re
* the queue is known to run
* but an earlier request may be stuck
* we may need to time out
- * no race because this is called under
- * spinlock
+ * release spinlock to avoid deadlock.
*/
- if (time_after(jiffies, usbhid->last_out + HZ * 5))
+ if (time_after(jiffies, usbhid->last_out + HZ * 5)) {
+ spin_unlock(&usbhid->lock);
usb_unlink_urb(usbhid->urbout);
+ spin_lock(&usbhid->lock);
+ }
}
return;
}
@@ -591,11 +593,13 @@ static void __usbhid_submit_report(struct hid_device *hid, struct hid_report *re
* the queue is known to run
* but an earlier request may be stuck
* we may need to time out
- * no race because this is called under
- * spinlock
+ * release spinlock to avoid deadlock.
*/
- if (time_after(jiffies, usbhid->last_ctrl + HZ * 5))
+ if (time_after(jiffies, usbhid->last_ctrl + HZ * 5)) {
+ spin_unlock(&usbhid->lock);
usb_unlink_urb(usbhid->urbctrl);
+ spin_lock(&usbhid->lock);
+ }
}
}
--
1.7.9.5
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