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badpage: zap print_bad_pte on swap and file

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Complete zap_pte_range()'s coverage of bad pagetable entries by calling
print_bad_pte() on a pte_file in a linear vma and on a bad swap entry.
That needs free_swap_and_cache() to tell it, which will also have shown
one of those "swap_free" errors (but with much less information).

Similar checks in fork's copy_one_pte()?  No, that would be more noisy
than helpful: we'll see them when parent and child exec or exit.

Where do_nonlinear_fault() calls print_bad_pte(): omit !VM_CAN_NONLINEAR
case, that could only be a bug in sys_remap_file_pages(), not a bad pte.
VM_FAULT_OOM rather than VM_FAULT_SIGBUS?  Well, okay, that is consistent
with what happens if do_swap_page() operates a bad swap entry; but don't
we have patches to be more careful about killing when VM_FAULT_OOM?

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2009-01-06 14:40:10 -08:00 committed by Linus Torvalds
parent 22b31eec63
commit 2509ef26db
3 changed files with 14 additions and 16 deletions
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12
include/linux/swap.h
View File

@ -302,7 +302,7 @@ extern swp_entry_t get_swap_page_of_type(int);
extern int swap_duplicate(swp_entry_t);
extern int valid_swaphandles(swp_entry_t, unsigned long *);
extern void swap_free(swp_entry_t);
extern void free_swap_and_cache(swp_entry_t);
extern int free_swap_and_cache(swp_entry_t);
extern int swap_type_of(dev_t, sector_t, struct block_device **);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
@ -352,14 +352,8 @@ static inline void show_swap_cache_info(void)
{
}
static inline void free_swap_and_cache(swp_entry_t swp)
{
}
static inline int swap_duplicate(swp_entry_t swp)
{
return 0;
}
#define free_swap_and_cache(swp) is_migration_entry(swp)
#define swap_duplicate(swp) is_migration_entry(swp)
static inline void swap_free(swp_entry_t swp)
{

11
mm/memory.c
View File

@ -810,8 +810,12 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
*/
if (unlikely(details))
continue;
if (!pte_file(ptent))
free_swap_and_cache(pte_to_swp_entry(ptent));
if (pte_file(ptent)) {
if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
print_bad_pte(vma, addr, ptent, NULL);
} else if
(unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent))))
print_bad_pte(vma, addr, ptent, NULL);
pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
} while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
@ -2707,8 +2711,7 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
return 0;
if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
!(vma->vm_flags & VM_CAN_NONLINEAR))) {
if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
/*
* Page table corrupted: show pte and kill process.
*/

7
mm/swapfile.c
View File

@ -571,13 +571,13 @@ int try_to_free_swap(struct page *page)
* Free the swap entry like above, but also try to
* free the page cache entry if it is the last user.
*/
void free_swap_and_cache(swp_entry_t entry)
int free_swap_and_cache(swp_entry_t entry)
{
struct swap_info_struct * p;
struct swap_info_struct *p;
struct page *page = NULL;
if (is_migration_entry(entry))
return;
return 1;
p = swap_info_get(entry);
if (p) {
@ -603,6 +603,7 @@ void free_swap_and_cache(swp_entry_t entry)
unlock_page(page);
page_cache_release(page);
}
return p != NULL;
}
#ifdef CONFIG_HIBERNATION