USB2+umass: timing related bug (machine check abort)
Hans Petter Selasky
hselasky at c2i.net
Tue Feb 17 08:22:36 PST 2009
On Tuesday 17 February 2009, Marcel Moolenaar wrote:
> Context: MACHINE=ia64, CPU=Montecito
>
> I'm running into a timing related MCA. In short:
> ...
> umass0: <HEWLETT PACKARD INTEGRITY SERVER, class 0/0, rev 2.00/0.a1,
> addr 2> on usbus2
> umass0: SCSI over Bulk-Only; quirks = 0x0000
> umass0:2:0:-1: Attached to scbus2
> *** machine check abort ***
> ***********************************************************
> * ROM Version : 01.05
> * ROM Date : 11/06/2006
> * BMC Version : 05.06
> ***********************************************************
> ...
>
> When I enable EHCI debugging (level 99) this does not happen
> and between the debug output, I see:
>
Hi,
I think that the problem is not USB related, but it happens at a point in time
where the UMASS USB transfer is half-setup. When the UMASS poll callback is
called at the wrong time, then you will get a NULL pointer access. Try the
following patch and report back:
http://perforce.freebsd.org/chv.cgi?CH=157847
--HPS
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