Strange panic on ppc64

[Nathan Whitehorn]

On 06/08/13 09:21, Justin Hibbits wrote:
>
>
>
> On Wed, Jun 5, 2013 at 9:47 AM, Justin Hibbits <jhibbits at freebsd.org
> <mailto:jhibbits at freebsd.org>> wrote:
>
>     Will do, when I get it panicking again.
>
>     - Justin
>
>     On Jun 5, 2013 9:46 AM, "Nathan Whitehorn" <nwhitehorn at freebsd.org
>     <mailto:nwhitehorn at freebsd.org>> wrote:
>
>         On 06/04/13 22:35, Justin Hibbits wrote:
>
>             After a string of seemingly random hangs, I added
>             invariants (but not
>             witness) to my custom kernel config, and I get the
>             following panic,
>             recreated from a fuzzy cell phone picture:
>
>
>             [thread pid -1 tid 1006665719 ]
>             Stopped at 0: illegal instruction 0
>             db> panic: mutex ohci1 owned at
>             /usr/home/chmeee/freebsd/head/sys/dev/usb/usb_transfer.c:2280
>             cpuid = 0
>             Uptime: 9h8m1s
>             <my dump code>
>             ...
>             panic: msleep1
>             cpu = 0
>             KDB: enter: panic
>             [ thread pid -1 tid 100665719 ]
>             ....
>
>             The first question I have is how the hell it got such a
>             strange PID/TID,
>             memory corruption my guess, something is stomping on the
>             pcpu or something,
>             and I think these hangs have only happened since I added a
>             lot more memory
>             (up to 12G from 4G, Andreas Tobler was seeing hangs as
>             well), so it might
>             be something in the moea64 pmap code, but that's pure
>             speculation on my
>             part.  Then the other panic messages, owned mutex and
>             panic in msleep1.  I
>             enabled more trace code, so hopefully the next time it
>             panics I can collect
>             better data.
>
>             - Justin
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>
>
>         Could you post the output from show reg? It looks like it
>         tried to jump to a null pointer there.
>         -Nathan
>
>
> Well, it's hard to do get that output, because I just hit that 'mutex
> owned' panic, and here's the backtrace:


The mutex thing is spurious -- it was already panicing and then paniced
again trying to panic. Can you get the backtrace for the original panic
(it should be different) and the values of the registers?
-Nathan