Re: Is this a git-bisect bug?

From: Teemu Likonen <tlikonen@iki.fi>
Date: Feb 21, 2009, 17:25 UTC
Message-ID: <87skm7em72.fsf@iki.fi>
In-Reply-To: <gnpccl$l69$1@ger.gmane.org>

On 2009-02-21 09:07 (-0800), walt wrote:

Show 14 quoted lines

> I'm using the current git.git to bisect a bug in Linus.git.
>
> I got this far and then ran into trouble:
> good 2.6.29-rc5-00094-gc951aa6
> bad  2.6.29-rc5-00112-g3501033
>
> A glance at git log will show that those two commits were
> both from Feb 17 with only one other commit between them.
>
> So, why does this happen?:
>
> $git bisect start 3501033 c951aa6
> Bisecting: 8 revisions left to test after this
> be716615fe596ee117292dc615e95f707fb67fd1] x86, vm86: fix preemption bug

Someone will probably give real explanation but non-linear development is part of it:

$ git log --graph --pretty=oneline --abbrev-commit c951aa6..3501033

*   3501033 Merge branch 'x86-fixes-for-linus' of git:// [...]
|\  
| * be71661 x86, vm86: fix preemption bug
| * e49590b x86, olpc: fix model detection without OFW
| * b13e246 x86, hpet: fix for LS21 + HPET = boot hang
| * 7ad9de6 x86: CPA avoid repeated lazy mmu flush
| * 34b0900 x86: warn if arch_flush_lazy_mmu_cpu is called in [...]
| * d85cf93 x86/paravirt: make arch_flush_lazy_mmu/cpu disable [...]
| * be03d9e x86, pat: fix warn_on_once() while mapping 0-1MB range [...]
| * 4f06b04 x86/cpa: make sure cpa is safe to call in lazy mmu mode
| * 9f339e7 x86, ptrace, mm: fix double-free on race
*   8ce9a75 Merge branch 'core-fixes-for-linus' of git:// [...]
|\  
| * 9af8814 iommu: fix Intel IOMMU write-buffer flushing
| * 2fff78c futex: fix reference leak
* b30b774 Merge branch 'merge' of git://git.kernel.org/pub/scm/ [...]
* 26456dc powerpc/vsx: Fix VSX alignment handler for regs 32-63
* 0047656 powerpc/ps3: Move ps3_mm_add_memory to device_initcall
* 06eccea powerpc/mm: Fix numa reserve bootmem page selection
* fbc78b0 powerpc/mm: Fix _PAGE_CHG_MASK to protect _PAGE_SPECIAL