Problem with git bisect in git-1.6.3.3

Problem with git bisect in git-1.6.3.3

[Chris Clayton]

Hi,

I'm using git bisect to track down a problem in 2.6.31-rc2 that is
locking up my laptop. I get so far in the bisection process and then
end up building a kernel that seems to me to be outside the good..bad
range. First time up I thought it might be a case of PBKAC, but I've
run the process again (very carefully) and got to the same place.

The bisect log so far:

[chris:~/kernel/linux-2.6]$ git bisect log
git bisect start
# good: [07a2039b8eb0af4ff464efd3dfd95de5c02648c6] Linux 2.6.30
git bisect good 07a2039b8eb0af4ff464efd3dfd95de5c02648c6
# bad: [8e4a718ff38d8539938ec3421935904c27e00c39] Linux 2.6.31-rc2
git bisect bad 8e4a718ff38d8539938ec3421935904c27e00c39
# good: [e7c5a4f292e0d1f4ba9a3a94b2c8e8b71e35b25a] powerpc/5121: make
clock debug output more readable
git bisect good e7c5a4f292e0d1f4ba9a3a94b2c8e8b71e35b25a
# bad: [d23c45fd84f79a3b84899dac053dcafe9d43ebc9] NFS: Invalid mount
option values should always fail, even with "sloppy"
git bisect bad d23c45fd84f79a3b84899dac053dcafe9d43ebc9
# bad: [2ed0e21b30b53d3a94e204196e523e6c8f732b56] Merge
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
git bisect bad 2ed0e21b30b53d3a94e204196e523e6c8f732b56

but, from Makefile, it appears the last "bad" has placed me at a
change earlier than 2.6.30:

[chris:~/kernel/linux-2.6]$ head Makefile
VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 30
EXTRAVERSION = -rc6
NAME = Vindictive Armadillo

# *DOCUMENTATION*
# To see a list of typical targets execute "make help"
# More info can be located in ./README
# Comments in this file are targeted only to the developer, do not

I'm not an experienced git user, so it may be that I have made an
error or false assumption. I guess it's also possible that I've
screwed my repository, although basically I only use two types of
command - pull a few times a week and the bisect family when I'm
trying to track down a problem.

Come to think of it, I did archive the repository (with tar | bzip2)
about a week ago whilst I changed the hard drive in my laptop. Once
the new drive was installed, I restored the repository and freshened
it up with a git pull. Could this be the root of my problem, please?

Happy to provide more information if needed. Please cc me to any reply
- I'm not subscribed.

Thanks

Chris

-- 
No, Sir; there is nothing which has yet been contrived by man, by
which so much happiness is produced as by a good tavern or inn -
Doctor Samuel Johnson

Re: Problem with git bisect in git-1.6.3.3

[Johannes Sixt]

Chris Clayton schrieb:
> git bisect start
> # good: [07a2039b8eb0af4ff464efd3dfd95de5c02648c6] Linux 2.6.30
> git bisect good 07a2039b8eb0af4ff464efd3dfd95de5c02648c6
> # bad: [8e4a718ff38d8539938ec3421935904c27e00c39] Linux 2.6.31-rc2
...
> but, from Makefile, it appears the last "bad" has placed me at a
> change earlier than 2.6.30:
> 
> [chris:~/kernel/linux-2.6]$ head Makefile
> VERSION = 2
> PATCHLEVEL = 6
> SUBLEVEL = 30
> EXTRAVERSION = -rc6
...
> I'm not an experienced git user, so it may be that I have made an
> error or false assumption.

Not an error, but false assumptions:

http://thread.gmane.org/gmane.comp.version-control.git/99967/focus=99977

Just continue bisecting. If you can't test the version that bisect warps
you to because the feature where the bug happens is not present, mark that
revision as "good".

-- Hannes

Re: Problem with git bisect in git-1.6.3.3

[Chris Clayton]

Hannes,

Thanks for your reply.

2009/7/9 Johannes Sixt <j.sixt@viscovery.net>:
> Chris Clayton schrieb:
>> git bisect start
>> # good: [07a2039b8eb0af4ff464efd3dfd95de5c02648c6] Linux 2.6.30
>> git bisect good 07a2039b8eb0af4ff464efd3dfd95de5c02648c6
>> # bad: [8e4a718ff38d8539938ec3421935904c27e00c39] Linux 2.6.31-rc2
> ...
>> but, from Makefile, it appears the last "bad" has placed me at a
>> change earlier than 2.6.30:
>>
>> [chris:~/kernel/linux-2.6]$ head Makefile
>> VERSION = 2
>> PATCHLEVEL = 6
>> SUBLEVEL = 30
>> EXTRAVERSION = -rc6
> ...
>> I'm not an experienced git user, so it may be that I have made an
>> error or false assumption.
>
> Not an error, but false assumptions:
>
> http://thread.gmane.org/gmane.comp.version-control.git/99967/focus=99977
>
> Just continue bisecting. If you can't test the version that bisect warps
> you to because the feature where the bug happens is not present, mark that
> revision as "good".
>

Ah, it makes sense now. Thanks for your help.

Chris

> -- Hannes
>
>



-- 
No, Sir; there is nothing which has yet been contrived by man, by which
so much happiness is produced as by a good tavern or inn - Doctor Samuel
Johnson

Re: Problem with git bisect in git-1.6.3.3

[Christian Couder]

On Thursday 09 July 2009, Johannes Sixt wrote:
> Chris Clayton schrieb:
> > git bisect start
> > # good: [07a2039b8eb0af4ff464efd3dfd95de5c02648c6] Linux 2.6.30
> > git bisect good 07a2039b8eb0af4ff464efd3dfd95de5c02648c6
> > # bad: [8e4a718ff38d8539938ec3421935904c27e00c39] Linux 2.6.31-rc2
>
> ...
>
> > but, from Makefile, it appears the last "bad" has placed me at a
> > change earlier than 2.6.30:
> >
> > [chris:~/kernel/linux-2.6]$ head Makefile
> > VERSION = 2
> > PATCHLEVEL = 6
> > SUBLEVEL = 30
> > EXTRAVERSION = -rc6
>
> ...
>
> > I'm not an experienced git user, so it may be that I have made an
> > error or false assumption.
>
> Not an error, but false assumptions:
>
> http://thread.gmane.org/gmane.comp.version-control.git/99967/focus=99977
>
> Just continue bisecting. If you can't test the version that bisect warps
> you to because the feature where the bug happens is not present, mark
> that revision as "good".

For information, I added the following very short FAQ entry:

http://git.or.cz/gitwiki/GitFaq#Whydoes.22gitbisect.22makesmetestversionsoutsidethe.22good-bad.22range.3F

Thanks,
Christian.