3.2.45-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: jerry.hoemann@xxxxxx
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>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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 */
--
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