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Subject[PATCH]: Fix deadlock in USBIP driver (staging), linux-2.6.34-rc5
Hi,
When detaching a port from the client side (usbip --detach 0),
the event thread, on the server side, is going to deadlock.
The "eh" server thread is getting USBIP_EH_RESET event and calls:
-> stub_device_reset() -> usb_reset_device()
the USB framework is then calling back _in the same "eh" thread_ :
-> stub_disconnect() -> usbip_stop_eh() -> wait_for_completion()
the "eh" thread is being asleep forever, waiting for its own completion.
The patch checks if "eh" is the current thread, in usbip_stop_eh().

Please Cc me in reply, I'm not in the list.

b.r.

------------------

diff -Nur linux-2.6.34-rc5/drivers/staging/usbip/usbip_event.c
linux-2.6.34-rc5.new/drivers/staging/usbip/usbip_event.c
--- linux-2.6.34-rc5/drivers/staging/usbip/usbip_event.c 2010-04-20
01:29:56.000000000 +0200
+++ linux-2.6.34-rc5.new/drivers/staging/usbip/usbip_event.c
2010-04-22 17:07:36.249588273 +0200
@@ -116,6 +116,13 @@
void usbip_stop_eh(struct usbip_device *ud)
{
struct usbip_task *eh = &ud->eh;
+ int i_am_eh;
+
+ lock_kernel();
+ i_am_eh = (eh->thread == current);
+ unlock_kernel();
+ if (i_am_eh)
+ return; /* do not wait for myself */

wait_for_completion(&eh->thread_done);
usbip_dbg_eh("usbip_eh has finished\n");


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