The patch titled
badpage: vm_normal_page use print_bad_pte
has been removed from the -mm tree. Its filename was
badpage-vm_normal_page-use-print_bad_pte.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: badpage: vm_normal_page use print_bad_pte
From: Hugh Dickins <hugh@xxxxxxxxxxx>
print_bad_pte() is so far being called only when zap_pte_range() finds
negative page_mapcount, or there's a fault on a pte_file where it does not
belong. That's weak coverage when we suspect pagetable corruption.
Originally, it was called when vm_normal_page() found an invalid pfn: but
pfn_valid is expensive on some architectures and configurations, so 2.6.24
put that under CONFIG_DEBUG_VM (which doesn't help in the field), then
2.6.26 replaced it by a VM_BUG_ON (likewise).
Reinstate the print_bad_pte() in vm_normal_page(), but use a cheaper test
than pfn_valid(): memmap_init_zone() (used in bootup and hotplug) keep a
__read_mostly note of the highest_memmap_pfn, vm_normal_page() then check
pfn against that. We could call this pfn_plausible() or pfn_sane(), but I
doubt we'll need it elsewhere: of course it's not reliable, but gives much
stronger pagetable validation on many boxes.
Also use print_bad_pte() when the pte_special bit is found outside a
VM_PFNMAP or VM_MIXEDMAP area, instead of VM_BUG_ON.
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/internal.h | 1 +
mm/memory.c | 20 ++++++++++----------
mm/page_alloc.c | 4 ++++
3 files changed, 15 insertions(+), 10 deletions(-)
diff -puN mm/internal.h~badpage-vm_normal_page-use-print_bad_pte mm/internal.h
--- a/mm/internal.h~badpage-vm_normal_page-use-print_bad_pte
+++ a/mm/internal.h
@@ -49,6 +49,7 @@ extern void putback_lru_page(struct page
/*
* in mm/page_alloc.c
*/
+extern unsigned long highest_memmap_pfn;
extern void __free_pages_bootmem(struct page *page, unsigned int order);
/*
diff -puN mm/memory.c~badpage-vm_normal_page-use-print_bad_pte mm/memory.c
--- a/mm/memory.c~badpage-vm_normal_page-use-print_bad_pte
+++ a/mm/memory.c
@@ -467,21 +467,18 @@ static inline int is_cow_mapping(unsigne
struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
pte_t pte)
{
- unsigned long pfn;
+ unsigned long pfn = pte_pfn(pte);
if (HAVE_PTE_SPECIAL) {
- if (likely(!pte_special(pte))) {
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
- return pte_page(pte);
- }
- VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
+ if (likely(!pte_special(pte)))
+ goto check_pfn;
+ if (!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)))
+ print_bad_pte(vma, addr, pte, NULL);
return NULL;
}
/* !HAVE_PTE_SPECIAL case follows: */
- pfn = pte_pfn(pte);
-
if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
if (vma->vm_flags & VM_MIXEDMAP) {
if (!pfn_valid(pfn))
@@ -497,11 +494,14 @@ struct page *vm_normal_page(struct vm_ar
}
}
- VM_BUG_ON(!pfn_valid(pfn));
+check_pfn:
+ if (unlikely(pfn > highest_memmap_pfn)) {
+ print_bad_pte(vma, addr, pte, NULL);
+ return NULL;
+ }
/*
* NOTE! We still have PageReserved() pages in the page tables.
- *
* eg. VDSO mappings can cause them to exist.
*/
out:
diff -puN mm/page_alloc.c~badpage-vm_normal_page-use-print_bad_pte mm/page_alloc.c
--- a/mm/page_alloc.c~badpage-vm_normal_page-use-print_bad_pte
+++ a/mm/page_alloc.c
@@ -69,6 +69,7 @@ EXPORT_SYMBOL(node_states);
unsigned long totalram_pages __read_mostly;
unsigned long totalreserve_pages __read_mostly;
+unsigned long highest_memmap_pfn __read_mostly;
int percpu_pagelist_fraction;
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
@@ -2597,6 +2598,9 @@ void __meminit memmap_init_zone(unsigned
unsigned long pfn;
struct zone *z;
+ if (highest_memmap_pfn < end_pfn - 1)
+ highest_memmap_pfn = end_pfn - 1;
+
z = &NODE_DATA(nid)->node_zones[zone];
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
/*
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
origin.patch
linux-next.patch
mark-complex-bitopsh-inlines-as-__always_inline.patch
clocksource-pass-clocksource-to-read-callback.patch
clocksource-pass-clocksource-to-read-callback-sparc-cleanup.patch
bio-zero-inlined-bio_vec.patch
page_fault-retry-with-nopage_retry.patch
page_fault-retry-with-nopage_retry-fix.patch
page_fault-retry-with-nopage_retry-fix-fix.patch
mm-shmemc-fix-division-by-zero.patch
getrusage-fill-ru_maxrss-value.patch
memcg-handle-swap-caches.patch
memcg-handle-swap-caches-build-fix.patch
memcg-swap-cgroup-for-remembering-usage.patch
memcg-memswap-controller-core.patch
memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch
memcg-memswap-controller-core-swapcache-fixes.patch
memcg-revert-gfp-mask-fix.patch
memcg-check-group-leader-fix.patch
memcg-memoryswap-controller-fix-limit-check.patch
memcg-swapout-refcnt-fix.patch
memcg-hierarchy-avoid-unnecessary-reclaim.patch
inactive_anon_is_low-move-to-vmscan.patch
mm-introduce-zone_reclaim-struct.patch
mm-add-zone-nr_pages-helper-function.patch
mm-make-get_scan_ratio-safe-for-memcg.patch
memcg-add-null-check-to-page_cgroup_zoneinfo.patch
memcg-add-inactive_anon_is_low.patch
memcg-add-mem_cgroup_zone_nr_pages.patch
memcg-add-zone_reclaim_stat.patch
memcg-add-zone_reclaim_stat-reclaim-stat-trivial-fixes-fix.patch
memcg-remove-mem_cgroup_cal_reclaim.patch
memcg-show-reclaim-stat.patch
memcg-rename-scan-global-lru.patch
memcg-protect-prev_priority.patch
memcg-swappiness.patch
memcg-explain-details-and-test-document.patch
memcg-fix-swap-accounting-leak-v3.patch
memcg-fix-swap-accounting-leak-doc-fix.patch
memcg-fix-shmems-swap-accounting.patch
prio_tree-debugging-patch.patch
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