+ kernel-power-allow-hibernation-with-page_poison-sanity-checking.patch added to -mm tree

* + kernel-power-allow-hibernation-with-page_poison-sanity-checking.patch added to -mm tree
@ 2020-11-14  1:07 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2020-11-14  1:07 UTC (permalink / raw)
  To: david, glider, keescook, labbott, mateusznosek0, mhocko,
	mm-commits, rafael.j.wysocki, rppt, vbabka


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

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Vlastimil Babka <vbabka@suse.cz>
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/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>
---

 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(-)

--- a/include/linux/mm.h~kernel-power-allow-hibernation-with-page_poison-sanity-checking
+++ a/include/linux/mm.h
@@ -2903,6 +2903,7 @@ static inline void kernel_unpoison_pages
 #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
--- 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
@@ -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);
 		}
--- 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@suse.cz are

mm-slub-use-kmem_cache_debug_flags-in-deactivate_slab.patch
mm-page_alloc-clean-up-pageset-high-and-batch-update.patch
mm-page_alloc-calculate-pageset-high-and-batch-once-per-zone.patch
mm-page_alloc-remove-setup_pageset.patch
mm-page_alloc-simplify-pageset_update.patch
mm-page_alloc-cache-pageset-high-and-batch-in-struct-zone.patch
mm-page_alloc-move-draining-pcplists-to-page-isolation-users.patch
mm-page_alloc-disable-pcplists-during-memory-offline.patch
mm-page_alloc-disable-pcplists-during-memory-offline-fix.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


^ permalink raw reply	[flat|nested] 2+ messages in thread