Re: USB, NetBSD 7/amd64: crashes

[tlaronde%polynum.com@localhost]

On Tue, Jul 07, 2015 at 10:32:12AM +0200, Manuel Bouyer wrote:
> On Tue, Jul 07, 2015 at 08:40:11AM +0200, tlaronde%polynum.com@localhost wrote:
> > I have tried a netbsd-7 kernel and it crashes as well and the problem is
> > still with locking.
> 
> I'm not sure it is a locking problem. In the dmesg you provide there
> is "sd1: detached"; so it looks like the device is gone while still trying
> to access it.

Whether one or the other. May the kernel "release" the faulting device
before faulting? Furthermore, it is a bi-core, if the fault is on cpu1
are messages from cpu0 and cpu1 guaranteed to be ordered in dmesg? i.e.
can one be sure that if "sd1: detached" appears before uvm_fault
there is a resp. time ordering? And a cause/consequence link is
not guaranteed either with two cores?

I don't have, unfortunately, a single CPU node on which I could test
whether it happens or not in this not concurrent case. This could give
a supplementary indication about the level the problem is. (Can one
instruct NetBSD to use only one CPU without an ad-hoc kernel?)
-- 
        Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
                     http://www.kergis.com/
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