Re: Regression from 3.4.9 to 3.4.16 "stable" kernel

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Oct 29, 2012 at 09:47:22AM -0500, Jacob Shin wrote:
> On Mon, Oct 29, 2012 at 02:40:58PM +0000, Ben Hutchings wrote:
> > On Mon, 2012-10-29 at 10:22 -0400, Mark Lord wrote:
> > > On 12-10-29 02:46 AM, Willy Tarreau wrote:
> > > > On Mon, Oct 29, 2012 at 12:03:55AM -0400, Mark Lord wrote:
> > > >> My server here runs the 3.4.xx series of "stable" kernels.
> > > >> Until today, it was running 3.4.9.
> > > >> Today I tried to upgrade it to 3.4.16.
> > > >> It hangs in setup.c.
> > > >>
> > > >> I've isolated the fault down to this specific change
> > > >> that was made between 3.4.9 and 3.4.16.
> > > >> Reverting this change allows the system to boot/run normally again.
> > > >>
> > > >>
> > > >> --- linux-3.4.9/arch/x86/kernel/setup.c	2012-08-15 11:17:17.000000000 -0400
> > > >> +++ linux-3.4.16/arch/x86/kernel/setup.c	2012-10-28 13:36:33.000000000 -0400
> > > >> @@ -927,8 +927,21 @@
> > > >>
> > > >>  #ifdef CONFIG_X86_64
> > > >>  	if (max_pfn > max_low_pfn) {
> > > >> -		max_pfn_mapped = init_memory_mapping(1UL<<32,
> > > >> -						     max_pfn<<PAGE_SHIFT);
> > > >> +		int i;
> > > >> +		for (i = 0; i < e820.nr_map; i++) {
> > > >> +			struct e820entry *ei = &e820.map[i];
> > > >> +
> > > >> +			if (ei->addr + ei->size <= 1UL << 32)
> > > >> +				continue;
> > > >> +
> > > >> +			if (ei->type == E820_RESERVED)
> > > >> +				continue;
> > > >> +
> > > >> +			max_pfn_mapped = init_memory_mapping(
> > > >> +				ei->addr < 1UL << 32 ? 1UL << 32 : ei->addr,
> > > >> +				ei->addr + ei->size);
> > > >> +		}
> > > >> +
> > > >>  		/* can we preseve max_low_pfn ?*/
> > > >>  		max_low_pfn = max_pfn;
> > > >>  	}
> > > > 
> > > > For the record, it is this commit introduced in 3.4.16 :
> > > > 
> > > > commit efd5fa0c1a1d1b46846ea6e8d1a783d0d8a6a721
> > > > Author: Jacob Shin <jacob.shin@amd.com>
> > > > Date:   Thu Oct 20 16:15:26 2011 -0500
> > > > 
> > > >     x86: Exclude E820_RESERVED regions and memory holes above 4 GB from direct mapping.
> > > >     
> > > >     commit 1bbbbe779aabe1f0768c2bf8f8c0a5583679b54a upstream.
> > > >     
> > > >     On systems with very large memory (1 TB in our case), BIOS may report a
> > > >     reserved region or a hole in the E820 map, even above the 4 GB range. Exclude
> > > >     these from the direct mapping.
> > > >     
> > > >     [ hpa: this should be done not just for > 4 GB but for everything above the legacy
> > > >       region (1 MB), at the very least.  That, however, turns out to require significant
> > > >       restructuring.  That work is well underway, but is not suitable for rc/stable. ]
> > > >     
> > > >     Signed-off-by: Jacob Shin <jacob.shin@amd.com>
> > > >     Link: http://lkml.kernel.org/r/1319145326-13902-1-git-send-email-jacob.shin@amd.com
> > > >     Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
> > > >     Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > 
> > > > Willy
> > > 
> > > 
> > > Thanks, Willy.
> > > 
> > > I've also now downloaded linux-3.7.0-rc3, and it boots/runs without need for patching.
> > > So there's a fix somewhere in between that perhaps could also get backported to -stable.
> > 
> > Might well be:
> > 
> > commit 1f2ff682ac951ed82cc043cf140d2851084512df
> > Author: Yinghai Lu <yinghai@kernel.org>
> > Date:   Mon Oct 22 16:35:18 2012 -0700
> > 
> >     x86, mm: Use memblock memory loop instead of e820_RAM
> > 
> > However I'm not sure that this loop is correct either.  Yinghai, does
> > your version definitely iterate in increasing pfn order?  If not then
> > the max_pfn_mapped assignment must be conditional.
> 
> Hi, I believe these two commits in mainline should fix Alexander's failing
> machien:
> 
> 844ab6f993b1d32eb40512503d35ff6ad0c57030
> f82f64dd9f485e13f29f369772d4a0e868e5633a
> 
> This thread has some more details:
> 
> https://lkml.org/lkml/2012/10/21/157
> 
> Sorry, and thanks!

Thanks, I've queued these up now.

greg k-h