On Tue, May 07, 2013 at 10:14:54AM -0600, jerry.hoemann@xxxxxx wrote:
>
>
> Greg, Yinghai, ...
>
> Have you guys had a chance to consider this patch?
>
> I understand that in general we want to only apply commits
> from upstream, but with the changes to init_memory_mapping in
> the 3.9 kernel the change below isn't applicable.
>
> I have looked into applying the upstream commits from Yinghai
> from Nov last year, this gets fairly involved and wasn't sure
> you'd want the larger change back ported.
>
> If you could let me know your views to one of the above or to
> a third approach I'd be most appreciative as we would like to
> have 3.0-stable based distros 3.0-stable pick up the eventual
> fix as the current code panics during boot on our new system
> with the right memory configurations.
Thanks Jerry, I'm queuing this for the 3.5.y kernel as well.
Cheers,
--
Luis
>
>
> thanks
>
> Jerry Hoemann
>
> -------------------------------------------------------
>
> On Tue, Apr 30, 2013 at 03:15:55PM -0600, Jerry Hoemann wrote:
> Patch for 3.0-stable. Function find_early_table_space removed upstream.
>
> Fixes panic in alloc_low_page due to pgt_buf overflow during
> init_memory_mapping.
>
> find_early_table_space sizes pgt_buf based upon the size of the
> memory being mapped, but it does not take into account the alignment
> of the memory. When the region being mapped spans a 512GB (PGDIR_SIZE)
> alignment, a panic from alloc_low_pages occurs.
>
> kernel_physical_mapping_init takes into account PGDIR_SIZE alignment.
> This causes an extra call to alloc_low_page to be made. This extra call
> isn't accounted for by find_early_table_space and causes a kernel panic.
>
> Change is to take into account PGDIR_SIZE alignment in find_early_table_space.
>
> Signed-off-by: Jerry Hoemann <jerry.hoemann@xxxxxx>
> ---
>
> Resending to stable@xxxxxxxxxxxxxxx.
>
> Patch should be applicable to 3.2-stable and 3.4-stable also.
>
> Code in 2.6.34 is different and patch is not applicable.
>
>
>
> arch/x86/mm/init.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index c22c423..96c4577 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -44,11 +44,15 @@ static void __init find_early_table_space(struct map_range *mr, int nr_range)
> int i;
> unsigned long puds = 0, pmds = 0, ptes = 0, tables;
> unsigned long start = 0, good_end;
> + unsigned long pgd_extra = 0;
> phys_addr_t base;
>
> for (i = 0; i < nr_range; i++) {
> unsigned long range, extra;
>
> + if ((mr[i].end >> PGDIR_SHIFT) - (mr[i].start >> PGDIR_SHIFT))
> + pgd_extra++;
> +
> range = mr[i].end - mr[i].start;
> puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;
>
> @@ -73,6 +77,7 @@ static void __init find_early_table_space(struct map_range *mr, int nr_range)
> tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
> tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
> tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
> + tables += (pgd_extra * PAGE_SIZE);
>
> #ifdef CONFIG_X86_32
> /* for fixmap */
> --
> 1.8.1.4
>
> --
>
> ----------------------------------------------------------------------------
> Jerry Hoemann Software Engineer Hewlett-Packard/MODL
>
> 3404 E Harmony Rd. MS 57 phone: (970) 898-1022
> Ft. Collins, CO 80528 FAX: (970) 898-XXXX
> email: jerry.hoemann@xxxxxx
> ----------------------------------------------------------------------------
>
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