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kernel/power: allow hibernation with page_poison sanity checking
Page poisoning used to be incompatible with hibernation, as the state of poisoned pages was lost after resume, thus enabling CONFIG_HIBERNATION forces CONFIG_PAGE_POISONING_NO_SANITY. For the same reason, the poisoning with zeroes variant CONFIG_PAGE_POISONING_ZERO used to disable hibernation. The latter restriction was removed by commit1ad1410f63
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and similarly for init_on_free by commit18451f9f9e
("PM: hibernate: fix crashes with init_on_free=1") by making sure free pages are cleared after resume. We can use the same mechanism to instead poison free pages with PAGE_POISON after resume. This covers both zero and 0xAA patterns. Thus we can remove the Kconfig restriction that disables page poison sanity checking when hibernation is enabled. Link: https://lkml.kernel.org/r/20201113104033.22907-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [hibernation] Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Laura Abbott <labbott@kernel.org> Cc: Mateusz Nosek <mateusznosek0@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5 changed files with 14 additions and 6 deletions
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@ -2903,6 +2903,7 @@ static inline void kernel_unpoison_pages(struct page *page, int numpages)
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#else
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static inline bool page_poisoning_enabled(void) { return false; }
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static inline bool page_poisoning_enabled_static(void) { return false; }
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static inline void __kernel_poison_pages(struct page *page, int nunmpages) { }
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static inline void kernel_poison_pages(struct page *page, int numpages) { }
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static inline void kernel_unpoison_pages(struct page *page, int numpages) { }
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#endif
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@ -326,7 +326,7 @@ static int create_image(int platform_mode)
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if (!in_suspend) {
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events_check_enabled = false;
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clear_free_pages();
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clear_or_poison_free_pages();
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}
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platform_leave(platform_mode);
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@ -106,7 +106,7 @@ extern int create_basic_memory_bitmaps(void);
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extern void free_basic_memory_bitmaps(void);
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extern int hibernate_preallocate_memory(void);
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extern void clear_free_pages(void);
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extern void clear_or_poison_free_pages(void);
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/**
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* Auxiliary structure used for reading the snapshot image data and
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@ -1178,7 +1178,15 @@ void free_basic_memory_bitmaps(void)
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pr_debug("Basic memory bitmaps freed\n");
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}
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void clear_free_pages(void)
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static void clear_or_poison_free_page(struct page *page)
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{
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if (page_poisoning_enabled_static())
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__kernel_poison_pages(page, 1);
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else if (want_init_on_free())
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clear_highpage(page);
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}
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void clear_or_poison_free_pages(void)
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{
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struct memory_bitmap *bm = free_pages_map;
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unsigned long pfn;
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@ -1186,12 +1194,12 @@ void clear_free_pages(void)
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if (WARN_ON(!(free_pages_map)))
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return;
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if (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) || want_init_on_free()) {
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if (page_poisoning_enabled() || want_init_on_free()) {
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memory_bm_position_reset(bm);
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pfn = memory_bm_next_pfn(bm);
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while (pfn != BM_END_OF_MAP) {
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if (pfn_valid(pfn))
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clear_highpage(pfn_to_page(pfn));
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clear_or_poison_free_page(pfn_to_page(pfn));
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pfn = memory_bm_next_pfn(bm);
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}
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@ -64,7 +64,6 @@ config PAGE_OWNER
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config PAGE_POISONING
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bool "Poison pages after freeing"
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select PAGE_POISONING_NO_SANITY if HIBERNATION
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help
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Fill the pages with poison patterns after free_pages() and verify
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the patterns before alloc_pages. The filling of the memory helps
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