From: Andrea Arcangeli <andrea@suse.de>
Reject zero page vm-area request, align size properly and hide the guard page
from the callers like ioremap - this avoids a kernel crash due one more page
being passed to change_page_attr().
Signed-off-by: Andrea Arcangeli <andrea@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/mm/ioremap.c | 6 +++---
25-akpm/arch/x86_64/mm/ioremap.c | 4 ++--
25-akpm/mm/vmalloc.c | 15 +++++++++++----
3 files changed, 16 insertions(+), 9 deletions(-)
diff -puN arch/i386/mm/ioremap.c~pageattr-guard-page arch/i386/mm/ioremap.c
--- 25/arch/i386/mm/ioremap.c~pageattr-guard-page 2004-12-03 20:04:25.803149608 -0800
+++ 25-akpm/arch/i386/mm/ioremap.c 2004-12-03 20:04:25.809148696 -0800
@@ -195,9 +195,9 @@ void __iomem *ioremap_nocache (unsigned
return p;
/* Guaranteed to be > phys_addr, as per __ioremap() */
- last_addr = phys_addr + size - 1;
+ last_addr = phys_addr + size;
- if (last_addr < virt_to_phys(high_memory)) {
+ if (last_addr <= virt_to_phys(high_memory)) {
struct page *ppage = virt_to_page(__va(phys_addr));
unsigned long npages;
@@ -232,7 +232,7 @@ void iounmap(volatile void __iomem *addr
return;
}
- if ((p->flags >> 24) && p->phys_addr < virt_to_phys(high_memory)) {
+ if ((p->flags >> 24) && p->phys_addr + p->size <= virt_to_phys(high_memory)) {
change_page_attr(virt_to_page(__va(p->phys_addr)),
p->size >> PAGE_SHIFT,
PAGE_KERNEL);
diff -puN arch/x86_64/mm/ioremap.c~pageattr-guard-page arch/x86_64/mm/ioremap.c
--- 25/arch/x86_64/mm/ioremap.c~pageattr-guard-page 2004-12-03 20:04:25.804149456 -0800
+++ 25-akpm/arch/x86_64/mm/ioremap.c 2004-12-03 20:04:25.809148696 -0800
@@ -195,7 +195,7 @@ void __iomem *ioremap_nocache (unsigned
if (!p)
return p;
- if (phys_addr + size - 1 < virt_to_phys(high_memory)) {
+ if (phys_addr + size <= virt_to_phys(high_memory)) {
struct page *ppage = virt_to_page(__va(phys_addr));
unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -223,7 +223,7 @@ void iounmap(volatile void __iomem *addr
return;
}
- if ((p->flags >> 24) && p->phys_addr + p->size < virt_to_phys(high_memory)) {
+ if ((p->flags >> 24) && p->phys_addr + p->size <= virt_to_phys(high_memory)) {
change_page_attr(virt_to_page(__va(p->phys_addr)),
p->size >> PAGE_SHIFT,
PAGE_KERNEL);
diff -puN mm/vmalloc.c~pageattr-guard-page mm/vmalloc.c
--- 25/mm/vmalloc.c~pageattr-guard-page 2004-12-03 20:04:25.806149152 -0800
+++ 25-akpm/mm/vmalloc.c 2004-12-03 20:04:25.810148544 -0800
@@ -199,20 +199,22 @@ struct vm_struct *__get_vm_area(unsigned
align = 1ul << bit;
}
addr = ALIGN(start, align);
+ size = PAGE_ALIGN(size);
area = kmalloc(sizeof(*area), GFP_KERNEL);
if (unlikely(!area))
return NULL;
- /*
- * We always allocate a guard page.
- */
- size += PAGE_SIZE;
if (unlikely(!size)) {
kfree (area);
return NULL;
}
+ /*
+ * We always allocate a guard page.
+ */
+ size += PAGE_SIZE;
+
write_lock(&vmlist_lock);
for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) {
if ((unsigned long)tmp->addr < addr) {
@@ -292,6 +294,11 @@ found:
unmap_vm_area(tmp);
*p = tmp->next;
write_unlock(&vmlist_lock);
+
+ /*
+ * Remove the guard page.
+ */
+ tmp->size -= PAGE_SIZE;
return tmp;
}
_