diff options
| author | Yang Shi <yang.shi@linaro.org> | 2016-06-03 14:55:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-06-03 15:06:22 -0700 |
| commit | f86e4271978bd93db466d6a95dad4b0fdcdb04f6 (patch) | |
| tree | 26ef29934495da598a11c3a177d0294a71c5eae8 /mm/page_poison.c | |
| parent | d8bae33dddc03dc652e1d8cfceebf4f753939de7 (diff) | |
mm: check the return value of lookup_page_ext for all call sites
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.org
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>
Diffstat (limited to 'mm/page_poison.c')
| -rw-r--r-- | mm/page_poison.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/page_poison.c b/mm/page_poison.c index 1eae5fad2446..2e647c65916b 100644 --- a/mm/page_poison.c +++ b/mm/page_poison.c @@ -54,6 +54,9 @@ static inline void set_page_poison(struct page *page) struct page_ext *page_ext; page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + return; + __set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); } @@ -62,6 +65,9 @@ static inline void clear_page_poison(struct page *page) struct page_ext *page_ext; page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + return; + __clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); } @@ -70,7 +76,7 @@ bool page_is_poisoned(struct page *page) struct page_ext *page_ext; page_ext = lookup_page_ext(page); - if (!page_ext) + if (unlikely(!page_ext)) return false; return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); |