| Message ID | 20201113104033.22907-4-vbabka@suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cleanup page poisoning | expand |
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@suse.cz> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> # 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@redhat.com>
On 11/13/20 1:10 PM, David Hildenbrand wrote: >> @@ -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? It's a single check per resume, so not worth live-patching this place. > Reviewed-by: David Hildenbrand <david@redhat.com> > >
On 13.11.20 13:15, Vlastimil Babka wrote: > On 11/13/20 1:10 PM, David Hildenbrand wrote: >>> @@ -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? > > It's a single check per resume, so not worth live-patching this place. Agreed, thanks.
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()) { 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); } diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 864f129f1937..c57786ad5be9 100644 --- a/mm/Kconfig.debug +++ b/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
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@suse.cz> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> # 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(-)