On Thu, Sep 30, Hubert Tonneau wrote:

> Copying a large amount of datas (several gigabytes) between two USB 2.0 attached
> disks will crash any Linux 2.6 SMP kernel, including 2.6.9-rc3.
> 
> The stack report is:
> qh_completions 0x7B/0x118 [ehci_hcd]

this was fixed a while ago, but not yet synced with Linus.

...
Maybe the call chain is something like this:

ehci_irq
spin_lock (&ehci->lock)
  ehci_work                             ehci_watchdog
    end_unlink_async
      qh_completions
        ehci_urb_done
        spin_unlock (&ehci->lock)
          usb_hcd_giveback_urb          spin_lock (&ehci->lock)
                                          ehci_work

now ehci_watchdog could proceed until usb_hcd_giveback_urb returns, then 
ehci_urb_done must wait until the watchdog is done. both seem to operate  
on the same list. I cant test it right now, box crashed.
...


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USB is for mice, FireWire is for men!

sUse lINUX ag, nÜRNBERG