Re: 2.6.21-rc1: known regressions (part 2)

[Ingo Molnar <mingo@elte.hu>]

* Ingo Molnar <mingo@elte.hu> wrote:

> hm. There's some weird bisection artifact here. Here are the commits i 
> tested, in git-log order:
> 
> #1 commit 01363220f5d23ef68276db8974e46a502e43d01d bad
> #2 commit ee404566f97f9254433399fbbcfa05390c7c55f7 bad
> #3 commit f3ccb06f3b8e0cf42b579db21f3ca7f17fcc3f38 good
> #4 commit c827ba4cb49a30ce581201fd0ba2be77cde412c7 bad
> 
> if i tell git-bisect that #1 is bad and #3 is good, then it offers me 
> #2 - that's OK. But when i tell it that #2 is bad, it offers #4 - 
> which is out of order! The bisection goes off into la-la land after 
> that and never gets back to a commit that is /after/ the good commit. 
> How is this possible? (I upgraded from git-1.4.4 to 1.5.0 to make sure 
> this isnt some git bug that's already fixed.)
> 
> i'll try to straighten this out manually, perhaps #3 is in some merge 
> branch that confuses bisection. Or maybe i misunderstood how 
> git-bisect works.

git-bisect gets royally confused on those ACPI merge branches around 
commit c0cd79d11412969b6b8fa1624cdc1277db82e2fe. Here are my test 
results so far:

 commit 01363220f5d23ef68276db8974e46a502e43d01d: bad
 commit 255f0385c8e0d6b9005c0e09fffb5bd852f3b506: bad
 commit c0cd79d11412969b6b8fa1624cdc1277db82e2fe: bad
 commit c24e912b61b1ab2301c59777134194066b06465c: good
 commit e9e2cdb412412326c4827fc78ba27f410d837e6e: bad
 commit 79bf2bb335b85db25d27421c798595a2fa2a0e82: bad
 commit fc955f670c0a66aca965605dae797e747b2bef7d: good
 commit 70c0846e430881967776582e13aefb81407919f1: good
 commit 414f827c46973ba39320cfb43feb55a0eeb9b4e8: bad
 commit f3ccb06f3b8e0cf42b579db21f3ca7f17fcc3f38: good
 commit 5f0b1437e0708772b6fecae5900c01c3b5f9b512: bad
 commit b878ca5d37953ad1c4578b225a13a3c3e7e743b7: bad
 commit c2902c8ae06762d941fab64198467f78cab6f8cd: bad
 commit 12e74f7d430655f541b85018ea62bcd669094bd7: bad
 commit 3388c37e04ec0e35ebc1b4c732fdefc9ea938f3b: bad
 commit 9f4bd5dde81b5cb94e4f52f2f05825aa0422f1ff: bad

the results are totally reproducible (i re-tried a few of both the good 
and the bad commits), i.e. it's not a sporadic condition. Also, a number 
of the 'bad' commits have no dynticks stuff in them at all, so i'd 
exclude dynticks.

could someone suggest a sane way to go with this? Perhaps suggest 
specific commit IDs to test?

	Ingo