Repeated crashes in 6.3-PRERELEASE

[Kris Kennaway]

Frank Mayhar wrote:
> On Sat, 2007-12-29 at 11:28 -0800, Frank Mayhar wrote:
>> This is on a very recent -stable (like, as of just a couple of days
>> ago).  Doing nothing in particular, ZERO_COPY_SOCKETS _not_ specified in
>> the config.  This has happened twice this morning; if it happens again
>> I'll drop back to my older kernel, built back in May.
> 
> Sigh.  In the last three days I've had no fewer than four crashes:  This
> one, another just like it that I didn't get a dump for, a "Fatal trap
> 12: page fault while in kernel mode" in buf_splay():
> 
> #27 0xffffffff802e2cb4 in buf_splay (lblkno=0, xflags=2 '\002', root=0x9000)
>     at /usr/src/sys/kern/vfs_subr.c:1339
> #28 0xffffffff802e2e08 in buf_vlist_remove (bp=0xffffffffa1919340)
>     at /usr/src/sys/kern/vfs_subr.c:1371
> #29 0xffffffff802e4dab in brelvp (bp=0xffffffffa1919340)
>     at /usr/src/sys/kern/vfs_subr.c:1502
> #30 0xffffffff802d28f1 in getnewbuf (slpflag=0, slptimeo=0, size=2, 
>     maxsize=16384) at /usr/src/sys/kern/vfs_bio.c:1801
> 
> (where bp->b_left is 0x9000)
> 
> and a "panic: backgroundwritedone: lost buffer."  I have a dump for each
> of the three unique scenarios.  At the moment I've dropped back to the
> older kernel and am keeping my fingers crossed that it will run okay.
> I'm beginning to suspect hardware, although as two of the three are in
> the buf code there might be a problem there...  If it continues with the
> older kernel then it is most likely hardware but if not then there's a
> problem.
> 
> Has anyone else encountered anything like this in 6.3-PRERELEASE?

Sounds pretty unusual (and e.g. I've not seen other reports of this), 
but if you are *still* able to run an older kernel without incident then 
maybe there was an intervening change that interacts badly with your 
particular hardware.  A binary search might be necessary to determine 
the cause, in that case.

Kris