Re: USB deadlock in v2.5.67

[David Brownell <david-b@pacbell.net>]

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Greg KH wrote:
> On Thu, Apr 17, 2003 at 07:02:07PM -0700, David Mosberger wrote:
> 
>><hcd_free_dev+0x140> translates into line 1249 in hcd.c, where it
>>does:
>>
>>	spin_lock_irqsave (&hcd_data_lock, flags);
>>
>>The deadlock is pretty obvious: the same lock has already been
>>acquired urb_unlink(), 4 levels up in the call-chain.
>>
>>Anybody have a fix for this?
> 
> 
> David (Brownell, that is), does this help with the trace I sent you a
> few hours ago?

Seems to be a different problem.  The patch below should
resolve the keyboard problem -- just reorders two lines
so the lock isn't held after the device's records get
deleted, so the order is what it should always have been.

- Dave





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--- 1.59/drivers/usb/core/hcd.c	Mon Apr 14 14:01:44 2003
+++ edited/drivers/usb/core/hcd.c	Fri Apr 18 08:20:42 2003
@@ -961,8 +961,8 @@
 	spin_lock_irqsave (&hcd_data_lock, flags);
 	list_del_init (&urb->urb_list);
 	dev = urb->dev;
-	usb_put_dev (dev);
 	spin_unlock_irqrestore (&hcd_data_lock, flags);
+	usb_put_dev (dev);
 }