freebsd stable - Aug 2015 - 8-stable crashing recently in ufsdirhash

On August 5, 2015 4:10:14 AM HST, Ian L
wrote:
>On Tue, 2015-08-04 at 23:54 -1000, parv wrote:
>> Please CC me as I cannot properly use my laptop, Thinkpad X200
>(i386).
>> 
>> 8-stable has been crashing a lot since source update of Jul 2015[0].
>After building debug kernel, kgdb shows lock reversal order & in
>ufsdirhash. File systems (/, var, misc) are all UFS, with var & misc
>having soft updates enabled.
>> 
>> Crash had happened just after boot (during mktemp); when I tried to
>delete a directory (/misc/obj); when I tried to edit (vi /etc/fstab) so
>that / would be mounted readonly. Most recent crash ...
>> 
>> http://imagebin.ca/v/2B50NARvIHsH
>> 
>> Any clue would be appreciated.
...
>When you say you built a debug kernel, does that include option
>WITNESS_KDB?  If so, remove that so you can find the real error.  LORs
>related to ufs_dirhash have been reported for years, and nobody with
>the
>appropriate skills seems to be interested in fixing them; they just get
>declared to be harmless.
I will try that as soon as I can. Currently after every little fs operation, I
am thrown in debugger-reboot-fsck cycle. As such I cannot do anything.

This is my own damn fault because the non-debug kernel would run for some random
but meaningful amount of time before crash & reboot. I tried booting
/boot/kernel.old/kernel from boot prompt but that presented debugger soon after
boot.

BTW is it possible to set kernel.old to boot next time at boot prompt?


--

On Wed, 05 Aug 2015 09:30:28 -1000 parv <parv at bitter-almonds.com> wrote
> On August 5, 2015 4:10:14 AM HST, Ian L
> wrote:
> >On Tue, 2015-08-04 at 23:54 -1000, parv wrote:
> >> Please CC me as I cannot properly use my laptop, Thinkpad X200
> >(i386).
> >> 
> >> 8-stable has been crashing a lot since source update of Jul
2015[0].
> >After building debug kernel, kgdb shows lock reversal order & in
> >ufsdirhash. File systems (/, var, misc) are all UFS, with var &
misc
> >having soft updates enabled.
> >> 
> >> Crash had happened just after boot (during mktemp); when I tried
to
> >delete a directory (/misc/obj); when I tried to edit (vi /etc/fstab) so
> >that / would be mounted readonly. Most recent crash ...
> >> 
> >> http://imagebin.ca/v/2B50NARvIHsH
> >> 
> >> Any clue would be appreciated.
> ...
> >When you say you built a debug kernel, does that include option
> >WITNESS_KDB?  If so, remove that so you can find the real error.  LORs
> >related to ufs_dirhash have been reported for years, and nobody with
> >the
> >appropriate skills seems to be interested in fixing them; they just get
> >declared to be harmless.
> 
> I will try that as soon as I can. Currently after every little fs
operation,
> I am thrown in debugger-reboot-fsck cycle. As such I cannot do anything.
> 
> This is my own damn fault because the non-debug kernel would run for some
> random but meaningful amount of time before crash & reboot. I tried
booting
> /boot/kernel.old/kernel from boot prompt but that presented debugger soon
> after boot. 
>
> BTW is it possible to set kernel.old to boot next time at boot prompt?
It might be somewhat easier to boot from the boot-only/install
CD/DVD, and then choose rescue mode.
After you've gotten there. Simply mount "/" in read/write, them
open
it's /boot/loader.conf, and add the following:
kernel="kernel.old"
boot_single="YES"

and save it. You can then remove the CD/DVD, and reboot which will land
you in single-user mode, from your kernel.old/kernel.
Assuming it booted to that kernel OK, you can run fsck -f
After it finishes, don't forget to re-edit /boot/loader.conf, and
comment those lines you added earlier -- well at least:
boot_single="YES"

HTH

--Chris
> 
> 
> -- 
> 
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