Re: debugging oops after disconnecting Nexio USB touchscreen

From: Oliver Neukum
Date: Wed Dec 02 2009 - 04:42:07 EST


Am Mittwoch, 2. Dezember 2009 09:52:08 schrieb Ondrej Zary:
> It shows "prev is NULL, qh=f6581080, ehci->async=f6581000".
>
> The problem is that activating usbmon causes the problem to disappear. No
> errors in maybe 15 attempts. It appeared on 2nd attempt after unloading
> usbmon.

That suggests a use after free bug, which usbmon prevents holding
an additional reference.
Are you using SLAB_DEBUG?

Regards
Oliver
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