The patch titled
Subject: kernel/power: allow hibernation with page_poison sanity checking
has been added to the -mm tree. Its filename is
kernel-power-allow-hibernation-with-page_poison-sanity-checking.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kernel-power-allow-hibernation-with-page_poison-sanity-checking.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kernel-power-allow-hibernation-with-page_poison-sanity-checking.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: 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 1ad1410f632d
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and
similarly for init_on_free by commit 18451f9f9e58 ("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/20201103152237.9853-4-vbabka@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Mateusz Nosek <mateusznosek0@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/power/hibernate.c | 2 +-
kernel/power/power.h | 2 +-
kernel/power/snapshot.c | 14 ++++++++++----
mm/Kconfig.debug | 1 -
4 files changed, 12 insertions(+), 7 deletions(-)
--- a/kernel/power/hibernate.c~kernel-power-allow-hibernation-with-page_poison-sanity-checking
+++ a/kernel/power/hibernate.c
@@ -326,7 +326,7 @@ static int create_image(int platform_mod
if (!in_suspend) {
events_check_enabled = false;
- clear_free_pages();
+ clear_or_poison_free_pages();
}
platform_leave(platform_mode);
--- a/kernel/power/power.h~kernel-power-allow-hibernation-with-page_poison-sanity-checking
+++ a/kernel/power/power.h
@@ -106,7 +106,7 @@ extern int create_basic_memory_bitmaps(v
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
--- a/kernel/power/snapshot.c~kernel-power-allow-hibernation-with-page_poison-sanity-checking
+++ a/kernel/power/snapshot.c
@@ -1172,7 +1172,7 @@ void free_basic_memory_bitmaps(void)
pr_debug("Basic memory bitmaps freed\n");
}
-void clear_free_pages(void)
+void clear_or_poison_free_pages(void)
{
struct memory_bitmap *bm = free_pages_map;
unsigned long pfn;
@@ -1180,12 +1180,18 @@ 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));
+ if (pfn_valid(pfn)) {
+ struct page *page = pfn_to_page(pfn);
+ if (page_poisoning_enabled_static())
+ kernel_poison_pages(page, 1);
+ else if (want_init_on_free())
+ clear_highpage(page);
+
+ }
pfn = memory_bm_next_pfn(bm);
}
--- a/mm/Kconfig.debug~kernel-power-allow-hibernation-with-page_poison-sanity-checking
+++ a/mm/Kconfig.debug
@@ -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
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-slub-use-kmem_cache_debug_flags-in-deactivate_slab.patch
mm-page_alloc-do-not-rely-on-the-order-of-page_poison-and-init_on_alloc-free-parameters.patch
mm-page_poison-use-static-key-more-efficiently.patch
kernel-power-allow-hibernation-with-page_poison-sanity-checking.patch
mm-page_poison-remove-config_page_poisoning_no_sanity.patch
mm-page_poison-remove-config_page_poisoning_zero.patch
