On Mon, 22 Oct 2012, Artem S. Tashkinov wrote:
> OK, here's what the kernel prints with your patch:
>
> usb 6.1.4: ep 86 list del corruption prev: e5103b54 e5103a94 e51039d4
>
> A small delay before I got thousands of list_del corruption messages would
> have been nice, but I managed to catch the message anyway.
All right. Here's a new patch, which will print more information and
will provide a 10-second delay.
For this to be useful, you should capture a usbmon trace at the same
time. The relevant entries will show up in the trace shortly before
_and_ shortly after the error message appears.
Alan Stern
P.S.: It will help if you unplug as many of the other USB devices as
possible before running this test.
Index: usb-3.6/drivers/usb/core/hcd.c
===================================================================
--- usb-3.6.orig/drivers/usb/core/hcd.c
+++ usb-3.6/drivers/usb/core/hcd.c
@@ -1083,6 +1083,8 @@ EXPORT_SYMBOL_GPL(usb_calc_bus_time);
/*-------------------------------------------------------------------------*/
+static bool list_error;
+
/**
* usb_hcd_link_urb_to_ep - add an URB to its endpoint queue
* @hcd: host controller to which @urb was submitted
@@ -1193,6 +1195,25 @@ void usb_hcd_unlink_urb_from_ep(struct u
{
/* clear all state linking urb to this dev (and hcd) */
spin_lock(&hcd_urb_list_lock);
+ {
+ struct list_head *cur = &urb->urb_list;
+ struct list_head *prev = cur->prev;
+ struct list_head *next = cur->next;
+
+ if (prev->next != cur && !list_error) {
+ list_error = true;
+ dev_err(&urb->dev->dev,
+ "ep %x list del corruption prev: %p %p %p %p
%p\n",
+ urb->ep->desc.bEndpointAddress,
+ cur, prev, prev->next, next, next->prev);
+ dev_err(&urb->dev->dev,
+ "head %p urb %p urbprev %p urbnext %p\n",
+ &urb->ep->urb_list, urb,
+ list_entry(prev, struct urb, urb_list),
+ list_entry(next, struct urb, urb_list));
+ mdelay(10000);
+ }
+ }
list_del_init(&urb->urb_list);
spin_unlock(&hcd_urb_list_lock);
}
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