On 13.11.20 11:40, Vlastimil Babka wrote:
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.
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> # for hibernation
---
include/linux/mm.h | 1 +
kernel/power/hibernate.c | 2 +-
kernel/power/power.h | 2 +-
kernel/power/snapshot.c | 14 +++++++++++---
mm/Kconfig.debug | 1 -
5 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5ab5358be2b3..b15000085ff2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2891,6 +2891,7 @@ 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
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index d5d48404db37..559acef3fddb 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -329,7 +329,7 @@ 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);
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 24f12d534515..778bf431ec02 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -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
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index af534982062d..64b7aab9aee4 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -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()) {
Any reason why not to use the static version here?
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
