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 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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