Re: [-rc7 regression] Buggy commit: "mm: use aligned zone start forpfn_to_bitidx calculation"
From: Ingo Molnar
Date: Sat Feb 16 2013 - 03:30:03 EST
* Greg KH <greg@xxxxxxxxx> wrote:
> On Fri, Feb 15, 2013 at 12:44:26PM +0100, Ingo Molnar wrote:
> > [ Greg: -stable was Cc:-ed for this potentially buggy commit. ]
> > * Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> > > On Thu, Feb 14, 2013 at 7:08 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> > > > these three:
> > > >
> > > > 10d73e655cef mm: bootmem: fix free_all_bootmem_core() with odd bitmap alignment
> > > > c060f943d092 mm: use aligned zone start for pfn_to_bitidx calculation
> > > > c0232ae861df mm: memblock: fix wrong memmove size in memblock_merge_regions()
> > > >
> > > > might have highmem=512m boot parameter sensitivity.
> > >
> > > 10d73e655cef should not be related, as we are using nobootmem wrapper
> > > of memblock.
> > > c0232ae861df is copying less while using the blank slot in memblock
> > > memory or reserved array
> > > so it should be ok too.
> > >
> > > c060f943d092 may be related as you config does not have
> > > CONFIG_SPARSEMEM defined.
> > Right, that's the commit causing the x86 regression:
> > c060f943d0929f3e429c5d9522290584f6281d6e is the first bad commit
> > commit c060f943d0929f3e429c5d9522290584f6281d6e
> > Date: Fri Jan 11 14:31:51 2013 -0800
> > mm: use aligned zone start for pfn_to_bitidx calculation
> > I've given 6d92d4f (its parent commit) quite a bit of testing so
> > I'm 99% sure in the validity of this bisection result.
> > Involved parties Cc:-ed.
> > Revert attached below - it reverts cleanly and I'll test this
> > today, to see whether this solves the sporadic lockups.
> > Thanks,
> > Ingo
> > ------------------->
> > >From 6f3d5a8f38eb23f792b408d9bc8fee53a7d158f9 Mon Sep 17 00:00:00 2001
> > From: Ingo Molnar <mingo@xxxxxxxxxx>
> > Date: Fri, 15 Feb 2013 12:43:22 +0100
> > Subject: [PATCH] Revert "mm: use aligned zone start for pfn_to_bitidx
> > calculation"
> > This reverts commit c060f943d0929f3e429c5d9522290584f6281d6e.
> Let me know if I should be reverting this from the -stable releases.
It appears so - it definitely locks up here with the config I
sent. It appears to be a rare bug but a bug.
Would be nice to hear from the authors/ackers/pushers of the
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