Commit 03b6c9a3 authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

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 commit 1ad1410f
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and
similarly for init_on_free by commit 18451f9f ("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: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>	[hibernation]
Reviewed-by: default avatarDavid 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8db26a3d

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -2903,6 +2903,7 @@ static inline void kernel_unpoison_pages(struct page *page, int numpages) 
#else

static inline bool page_poisoning_enabled(void) { return false; }

static inline bool page_poisoning_enabled_static(void) { return false; }

static inline void __kernel_poison_pages(struct page *page, int nunmpages) { }

static inline void kernel_poison_pages(struct page *page, int numpages) { }

static inline void kernel_unpoison_pages(struct page *page, int numpages) { }

#endif

kernel/power/hibernate.c

+1 −1
Original line number Diff line number Diff line
@@ -326,7 +326,7 @@ static int create_image(int platform_mode) 


	if (!in_suspend) {

		events_check_enabled = false;

		clear_free_pages();

		clear_or_poison_free_pages();

	}



	platform_leave(platform_mode);

kernel/power/power.h

+1 −1
Original line number Diff line number Diff line
@@ -106,7 +106,7 @@ extern int create_basic_memory_bitmaps(void); 
extern void free_basic_memory_bitmaps(void);

extern int hibernate_preallocate_memory(void);



extern void clear_free_pages(void);

extern void clear_or_poison_free_pages(void);



/**

 *	Auxiliary structure used for reading the snapshot image data and

kernel/power/snapshot.c

+11 −3
Original line number Diff line number Diff line
@@ -1178,7 +1178,15 @@ void free_basic_memory_bitmaps(void) 
	pr_debug("Basic memory bitmaps freed\n");

}



void clear_free_pages(void)

static void clear_or_poison_free_page(struct page *page)

{

	if (page_poisoning_enabled_static())

		__kernel_poison_pages(page, 1);

	else if (want_init_on_free())

		clear_highpage(page);

}



void clear_or_poison_free_pages(void)

{

	struct memory_bitmap *bm = free_pages_map;

	unsigned long pfn;
@@ -1186,12 +1194,12 @@ void clear_free_pages(void) 
	if (WARN_ON(!(free_pages_map)))

		return;



	if (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) || want_init_on_free()) {

	if (page_poisoning_enabled() || want_init_on_free()) {

		memory_bm_position_reset(bm);

		pfn = memory_bm_next_pfn(bm);

		while (pfn != BM_END_OF_MAP) {

			if (pfn_valid(pfn))

				clear_highpage(pfn_to_page(pfn));

				clear_or_poison_free_page(pfn_to_page(pfn));



			pfn = memory_bm_next_pfn(bm);

		}

mm/Kconfig.debug

+0 −1
Original line number Diff line number Diff line
@@ -64,7 +64,6 @@ config PAGE_OWNER 


config PAGE_POISONING

	bool "Poison pages after freeing"

	select PAGE_POISONING_NO_SANITY if HIBERNATION

	help

	  Fill the pages with poison patterns after free_pages() and verify

	  the patterns before alloc_pages. The filling of the memory helps