Kernel 'bisection'

Scott Blair scott.blair at gmail.com
Sun Feb 15 00:16:26 UTC 2015


On 02/14/2015 05:20 PM, Chris wrote:
> On Sat, 2015-02-14 at 13:42 -0500, Scott Blair wrote:
>> On 02/14/2015 08:19 AM, Chris wrote:
>>> On Sat, 2015-02-14 at 13:05 +0000, Peter Waller wrote:
>>>> Briefly, bisection is a way of taking a long list of 1000's of
>>>> changes, and arranging things so that you only have to test more like
>>>> 10 of them, because you test midpoints. (and 2^10 ~ 1000).
>>>>
>>>>
>>>> More detail:
>>>>
>>>>
>>>> http://alblue.bandlem.com/2011/07/git-tip-of-week-git-bisect.html
>>>>
>>>>
>>>> On 14 February 2015 at 12:57, Liam Proven <lproven at gmail.com> wrote:
>>>>           On 14 February 2015 at 02:59, Chris <cpollock at embarqmail.com>
>>>>           wrote:
>>>>           > Who can give me some pointers on doing a kernel bisection on
>>>>           either
>>>>           > 3.13.0-35 or -36 kernels? Ever since one of those two were
>>>>           installed,
>>>>           > I'm on -45 now, my system will lockup (black screen, cursor
>>>>           moves, but
>>>>           > CTRL-ALT-F1 will not take me to a terminal log-in. This is
>>>>           the error I
>>>>           > see - Feb 13 19:05:22 localhost kernel: [807775.808019]
>>>>           > [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer
>>>>           elapsed... render
>>>>           > ring idle. I've reported this last year on Launchpad as bug
>>>>           -
>>>>           > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1402331
>>>>           I've jumped
>>>>           > through all the hoops that have been suggested there except
>>>>           doing a
>>>>           > kernel bisection which seems to have me confused. I'm really
>>>>           getting a
>>>>           > bit tired of these continued 'lockups'.
>>>>           
>>>>           
>>>>           I have to ask. WTF is a "kernel bisection"?
>>>>           
>>>>           You want to... cut your kernel in half? Is this some kind of
>>>>           Solomonic
>>>>           judgement? Because, you know, like half a baby doesn't work,
>>>>           half a
>>>>           kernel won't, either.
>>>>           
>>> That, to me, is as clear as mud just as these instructions on doing it
>>> are - https://wiki.ubuntu.com/Kernel/KernelBisection I can't live with
>>> having these 'lockups' every 2-10 days, more or less and I say that
>>> because it's so very random I have no idea what even triggers it.
>>>
>>>
>> Chris, I just had a lock up about 3 minutes go. I saw that my memory sky
>> rocketed, physical 99% and swap 90%. Normally they run low. CPU was
>> running normal when it happened. I was logging into a flash page when it
>> happened. The flash page finally crashed and everything went back to
>> normal. I am using Ubuntu 14. 04 kernel 3.13.0-45-generic and Chrome
>> 40.0.2214.111 64 bit. Don't know if this will help in your problem.
>>
>> -- 
>>
>> Scott Blair
>>
>> Save on back up time BackupDevice=Null
>>
>>
> I've had flash crash a few times since the latest update. Did the system
> 'lockup'? For instance I have my clock showing seconds when this happens
> to me the screen locks up however all background operations such as
> fetchmail, procmail, spamassassin and so forth continue to run. If you
> didn't see that type of a lockup then it must have just been flash.
> However you can check your syslog for kernel: [ 8248.820016]
> [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... render
> ring idle to see if you have the same issue.
>
> On another note I just tried to regress to the 3.13.0-35 kernel, system
> would boot but had no cursor and login screen didn't look right. Could
> not login so I removed it.
>
> So basically I'm back to where I was before just waiting for someone
> from either of the two bug reports to tell me what to do next and
> waiting for the next lockup.
>
> Chris
>
Yeah everything but the mouse stopped working. Don't know if anything 
was running in the "background"
Here is my syslog covering the times:
Feb 14 13:15:16 main NetworkManager[781]: <warn> nl_recvmsgs() error: 
(-33) Dump inconsistency detected, interrupted
Feb 14 13:17:01 main CRON[18418]: (root) CMD (   cd / && run-parts 
--report /etc/cron.hourly)
Feb 14 13:39:49 main dbus[704]: [system] Activating service 
name='org.freedesktop.hostname1' (using servicehelper)
Feb 14 13:39:49 main dbus[704]: [system] Successfully activated service 
'org.freedesktop.hostname1'
Feb 14 13:39:49 main kernel: [664854.867393] systemd-hostnamed[18912]: 
Warning: nss-myhostname is not installed. Changing the local hostname 
might make it unresolveable. Please install nss-myhostname!


-- 

Scott Blair

Save on back up time BackupDevice=Null




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