ChangeSet 1.1499, 2005/04/07 09:07:52-03:00, [EMAIL PROTECTED]
[PATCH] x86_64: Fix reference counting bug in change_page_attr on
i386/x86-64
Fix reference counting bug in change_page_attr on i386/x86-64
When not splitting a page the reference count must be increased too.
Found by several people in 2.6, one of them was Andrea Arcangelli, other
names I don't remember (sorry).
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
Index: linux/arch/i386/mm/pageattr.c
===================================================================
i386/mm/pageattr.c | 8 ++------
x86_64/mm/pageattr.c | 9 +++------
2 files changed, 5 insertions(+), 12 deletions(-)
diff -Nru a/arch/i386/mm/pageattr.c b/arch/i386/mm/pageattr.c
--- a/arch/i386/mm/pageattr.c 2005-04-07 11:04:03 -07:00
+++ b/arch/i386/mm/pageattr.c 2005-04-07 11:04:03 -07:00
@@ -119,19 +119,15 @@
kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK);
if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
- pte_t old = *kpte;
- pte_t standard = mk_pte(page, PAGE_KERNEL);
-
set_pte_atomic(kpte, mk_pte(page, prot));
- if (pte_same(old,standard))
- atomic_inc(&kpte_page->count);
} else {
struct page *split = split_large_page(address, prot);
if (!split)
return -ENOMEM;
- atomic_inc(&kpte_page->count);
set_pmd_pte(kpte,address,mk_pte(split, PAGE_KERNEL));
+ kpte_page = split;
}
+ atomic_inc(&kpte_page->count);
} else if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
atomic_dec(&kpte_page->count);
diff -Nru a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c
--- a/arch/x86_64/mm/pageattr.c 2005-04-07 11:04:03 -07:00
+++ b/arch/x86_64/mm/pageattr.c 2005-04-07 11:04:03 -07:00
@@ -101,18 +101,15 @@
kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK);
if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
- pte_t old = *kpte;
- pte_t standard = mk_pte(page, PAGE_KERNEL);
-
set_pte(kpte, mk_pte(page, prot));
- if (pte_same(old,standard))
- atomic_inc(&kpte_page->count);
} else {
struct page *split = split_large_page(address, prot);
if (!split)
return -ENOMEM;
set_pte(kpte,mk_pte(split, PAGE_KERNEL));
- }
+ kpte_page = split;
+ }
+ atomic_inc(&kpte_page->count);
} else if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
set_pte(kpte, mk_pte(page, PAGE_KERNEL));
atomic_dec(&kpte_page->count);
-
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