This is a note to let you know that I've just added the patch titled
mm: check the return value of lookup_page_ext for all call sites
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: mm-check-the-return-value-of-lookup_page_ext-for-all-call-sites.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From f86e4271978bd93db466d6a95dad4b0fdcdb04f6 Mon Sep 17 00:00:00 2001
From: Yang Shi yang.shi@linaro.org Date: Fri, 3 Jun 2016 14:55:38 -0700 Subject: mm: check the return value of lookup_page_ext for all call sites
From: Yang Shi yang.shi@linaro.org
commit f86e4271978bd93db466d6a95dad4b0fdcdb04f6 upstream.
Per the discussion with Joonsoo Kim [1], we need check the return value of lookup_page_ext() for all call sites since it might return NULL in some cases, although it is unlikely, i.e. memory hotplug.
Tested with ltp with "page_owner=0".
[1] http://lkml.kernel.org/r/20160519002809.GA10245@js1304-P5Q-DELUXE
[akpm@linux-foundation.org: fix build-breaking typos] [arnd@arndb.de: fix build problems from lookup_page_ext] Link: http://lkml.kernel.org/r/6285269.2CksypHdYp@wuerfel [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1464023768-31025-1-git-send-email-yang.shi@linaro.o... Signed-off-by: Yang Shi yang.shi@linaro.org Signed-off-by: Arnd Bergmann arnd@arndb.de Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Michal Hocko mhocko@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/page_idle.h | 43 ++++++++++++++++++++++++++++++++++++------- mm/debug-pagealloc.c | 6 ++++++ mm/page_alloc.c | 6 ++++++ mm/page_owner.c | 16 ++++++++++++++++ mm/vmstat.c | 2 ++ 5 files changed, 66 insertions(+), 7 deletions(-)
--- a/include/linux/page_idle.h +++ b/include/linux/page_idle.h @@ -46,33 +46,62 @@ extern struct page_ext_operations page_i
static inline bool page_is_young(struct page *page) { - return test_bit(PAGE_EXT_YOUNG, &lookup_page_ext(page)->flags); + struct page_ext *page_ext = lookup_page_ext(page); + + if (unlikely(!page_ext)) + return false; + + return test_bit(PAGE_EXT_YOUNG, &page_ext->flags); }
static inline void set_page_young(struct page *page) { - set_bit(PAGE_EXT_YOUNG, &lookup_page_ext(page)->flags); + struct page_ext *page_ext = lookup_page_ext(page); + + if (unlikely(!page_ext)) + return; + + set_bit(PAGE_EXT_YOUNG, &page_ext->flags); }
static inline bool test_and_clear_page_young(struct page *page) { - return test_and_clear_bit(PAGE_EXT_YOUNG, - &lookup_page_ext(page)->flags); + struct page_ext *page_ext = lookup_page_ext(page); + + if (unlikely(!page_ext)) + return false; + + return test_and_clear_bit(PAGE_EXT_YOUNG, &page_ext->flags); }
static inline bool page_is_idle(struct page *page) { - return test_bit(PAGE_EXT_IDLE, &lookup_page_ext(page)->flags); + struct page_ext *page_ext = lookup_page_ext(page); + + if (unlikely(!page_ext)) + return false; + + return test_bit(PAGE_EXT_IDLE, &page_ext->flags); }
static inline void set_page_idle(struct page *page) { - set_bit(PAGE_EXT_IDLE, &lookup_page_ext(page)->flags); + struct page_ext *page_ext = lookup_page_ext(page); + + if (unlikely(!page_ext)) + return; + + set_bit(PAGE_EXT_IDLE, &page_ext->flags); }
static inline void clear_page_idle(struct page *page) { - clear_bit(PAGE_EXT_IDLE, &lookup_page_ext(page)->flags); + struct page_ext *page_ext = lookup_page_ext(page); + + if (unlikely(!page_ext)) + return; + + clear_bit(PAGE_EXT_IDLE, &page_ext->flags); } #endif /* CONFIG_64BIT */
--- a/mm/debug-pagealloc.c +++ b/mm/debug-pagealloc.c @@ -34,6 +34,8 @@ static inline void set_page_poison(struc struct page_ext *page_ext;
page_ext = lookup_page_ext(page); + if (page_ext) + return; __set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); }
@@ -42,6 +44,8 @@ static inline void clear_page_poison(str struct page_ext *page_ext;
page_ext = lookup_page_ext(page); + if (page_ext) + return; __clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); }
@@ -50,6 +54,8 @@ static inline bool page_poison(struct pa struct page_ext *page_ext;
page_ext = lookup_page_ext(page); + if (page_ext) + return false; return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); }
--- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -569,6 +569,9 @@ static inline void set_page_guard(struct return;
page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + return; + __set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
INIT_LIST_HEAD(&page->lru); @@ -586,6 +589,9 @@ static inline void clear_page_guard(stru return;
page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + return; + __clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
set_page_private(page, 0); --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -53,6 +53,8 @@ void __reset_page_owner(struct page *pag
for (i = 0; i < (1 << order); i++) { page_ext = lookup_page_ext(page + i); + if (unlikely(!page_ext)) + continue; __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); } } @@ -60,6 +62,7 @@ void __reset_page_owner(struct page *pag void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) { struct page_ext *page_ext = lookup_page_ext(page); + struct stack_trace trace = { .nr_entries = 0, .max_entries = ARRAY_SIZE(page_ext->trace_entries), @@ -67,6 +70,9 @@ void __set_page_owner(struct page *page, .skip = 3, };
+ if (unlikely(!page_ext)) + return; + save_stack_trace(&trace);
page_ext->order = order; @@ -79,6 +85,12 @@ void __set_page_owner(struct page *page, gfp_t __get_page_owner_gfp(struct page *page) { struct page_ext *page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + /* + * The caller just returns 0 if no valid gfp + * So return 0 here too. + */ + return 0;
return page_ext->gfp_mask; } @@ -194,6 +206,8 @@ read_page_owner(struct file *file, char }
page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + continue;
/* * Some pages could be missed by concurrent allocation or free, @@ -257,6 +271,8 @@ static void init_pages_in_zone(pg_data_t continue;
page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + continue;
/* Maybe overraping zone */ if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1091,6 +1091,8 @@ static void pagetypeinfo_showmixedcount_ continue;
page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + continue;
if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) continue;
Patches currently in stable-queue which might be from yang.shi@linaro.org are
queue-4.4/mm-check-the-return-value-of-lookup_page_ext-for-all-call-sites.patch