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kernel/power: allow hibernation with page_poison sanity checking

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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 1ad1410f63
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and
similarly for init_on_free by commit 18451f9f9e ("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>
This commit is contained in:
Vlastimil Babka 2020-12-14 19:13:38 -08:00 committed by Linus Torvalds
parent 8db26a3d47
commit 03b6c9a3e8
5 changed files with 14 additions and 6 deletions
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1
include/linux/mm.h
View file

@ -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

2
kernel/power/hibernate.c
View file

@ -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);

2
kernel/power/power.h
View file

@ -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

14
kernel/power/snapshot.c
View file

@ -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);
}

1
mm/Kconfig.debug
View file

@ -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