Re: 2.6.25-rc hangs

Christian Kujau
2008-03-09T18:49:48Z

On Sun, 9 Mar 2008, Eric Sandeen wrote:
> I meant the test you were using to determine "good" from "bad" - I guess
> it was "boot up and do IO for a while to see if it hangs"

Maybe I was too confusing, let me try again:

* 2.6.24.1 was running fine for weeks (and is now)
* 2.6.25-rc3, -rc4 comes with system hang. Trying to bisect it failed
at a really early stage:

[check out current -git, 2.6.25-rc4)
$ git bisect start
$ git bisect bad # because I know, that current -git is bad
$ git bisect good v2.6.24 # because I know 2.6.24 is good
[ compiling, and first reboot]
-> failed, because hard lockup.

After rebooting to a working kernel I can now do either:

1) mark the current one as "bad", solely on the fact that "it does not
boot" and is "bad" per se, ignoring the fact that if the box *had*
booted, the system hang *perhaps* did not occur. IOW, I'm marking
it "bad" because of a totally different issue.

2) although booting failed, I still mark it "good", which means I'm
literally *guessing* that this current kernel (bd45ac0c5daa...)
does NOT have the system hang and thus affecting all subsequent
bisects. Worst case: this guess turns out to be false and I'm bisecting
all through all ~2800 revisions without ever getting the correct "bad"
one (because they were actually all "bad").

I tried 1), but did not get any further, as the next kernel did not boot
either.
I tried 2), but did not get any further, as the next kernel did boot but
locked up when I tried to use the device mapper.

Hope that's a bit better explained than before...

Thanks,
C.
--
BOFH excuse #58:

high pressure system failure