Re: amd64-7.0_STABLE trap panic

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

On Fri, 6 Nov 2015, John D. Baker wrote:

> Shortly after updating my file server to the latest 7.0_STABLE:
>
> NetBSD yggdrasil.technoskunk.fur 7.0_STABLE NetBSD 7.0_STABLE (YGGDRASIL) #120: Fri Nov  6 08:52:21 CST 2015  sysop%yggdrasil.technoskunk.fur@localhost:/r0/build/netbsd-7/obj/amd64/sys/arch/amd64/compile/YGGDRASIL amd64
>
> the machine panicked.  Upon reboot, the saved crash dump showed:
>
> $ crash -M netbsd.2.core -N netbsd.2
> Crash version 7.0_STABLE, image version 7.0_STABLE.
> System panicked: trap
> Backtrace from time of crash is available.
> crash> bt
> _KERNEL_OPT_NAGR() at 0
> _KERNEL_OPT_NAGR() at 0
> vpanic() at vpanic+0x145
> snprintf() at snprintf
> startlwp() at startlwp
> calltrap() at calltrap+0x11
> VOP_PUTPAGES() at VOP_PUTPAGES+0x3a
> uvm_pageout() at uvm_pageout+0x2f1
> crash>

This would seem to be at

(gdb) list *uvm_pageout+0x2f1
0xffffffff802d1bb3 is in uvm_pageout (/build/netbsd-local/src/sys/uvm/uvm_pdaemon.c:495).
490             KASSERT(swc->swc_nused < swc->swc_nallocated);
491             KASSERT((pg->pqflags & PQ_SWAPBACKED) != 0);
492
493             slot = swc->swc_slot + swc->swc_nused;
494             uobj = pg->uobject;
495             if (uobj == NULL) {
496                     KASSERT(mutex_owned(pg->uanon->an_lock));
497                     pg->uanon->an_swslot = slot;
498             } else {
499                     int result;
(gdb)

I don't have any further insight - I'm not at all familiar with the
pagedaemon code.


> The machine was building a -current release at the time as well as
> serving the various src/xsrc/pkgsrc trees to two NFS clients building
> -current for other architectures.  Also serving my home directory to
> a third client.
>
> The "_KERNEL_OPT_NAGR()" statements are puzzling.  They would appear to
> refer to the "agr" link-aggregation pseudo-device, but the running kernel
> omits that device, including GENERIC, then using "no pseudo-device agr".
>
> I don't know if I can repeat it, but if it happens again, I'll make note
> of it.  Anything else to look at in the crashdump?
>
> --
> |/"\ John D. Baker, KN5UKS               NetBSD     Darwin/MacOS X
> |\ / jdbaker[snail]mylinuxisp[flyspeck]com    OpenBSD            FreeBSD
> | X  No HTML/proprietary data in email.   BSD just sits there and works!
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| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:       |
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