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| 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_alloc.c | |
| parent | d8bae33dddc03dc652e1d8cfceebf4f753939de7 (diff) | |
| download | linux-f86e4271978bd93db466d6a95dad4b0fdcdb04f6.tar.gz linux-f86e4271978bd93db466d6a95dad4b0fdcdb04f6.tar.xz | |
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_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f8f3bfc435ee..d27e8b968ac3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -656,6 +656,9 @@ static inline void set_page_guard(struct zone *zone, struct page *page, 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); @@ -673,6 +676,9 @@ static inline void clear_page_guard(struct zone *zone, struct page *page, 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); |