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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_owner.c | |
| parent | d8bae33dddc03dc652e1d8cfceebf4f753939de7 (diff) | |
| download | linux-f86e4271978bd93db466d6a95dad4b0fdcdb04f6.tar.gz linux-f86e4271978bd93db466d6a95dad4b0fdcdb04f6.tar.bz2 linux-f86e4271978bd93db466d6a95dad4b0fdcdb04f6.zip | |
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_owner.c')
| -rw-r--r-- | mm/page_owner.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c index 792b56da13d8..c6cda3e36212 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -55,6 +55,8 @@ void __reset_page_owner(struct page *page, unsigned int order) 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); } } @@ -62,6 +64,7 @@ void __reset_page_owner(struct page *page, unsigned int order) 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), @@ -69,6 +72,9 @@ void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) .skip = 3, }; + if (unlikely(!page_ext)) + return; + save_stack_trace(&trace); page_ext->order = order; @@ -82,6 +88,8 @@ void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) void __set_page_owner_migrate_reason(struct page *page, int reason) { struct page_ext *page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + return; page_ext->last_migrate_reason = reason; } @@ -89,6 +97,12 @@ void __set_page_owner_migrate_reason(struct page *page, int reason) 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; } @@ -99,6 +113,9 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage) struct page_ext *new_ext = lookup_page_ext(newpage); int i; + if (unlikely(!old_ext || !new_ext)) + return; + new_ext->order = old_ext->order; new_ext->gfp_mask = old_ext->gfp_mask; new_ext->nr_entries = old_ext->nr_entries; @@ -193,6 +210,11 @@ void __dump_page_owner(struct page *page) gfp_t gfp_mask = page_ext->gfp_mask; int mt = gfpflags_to_migratetype(gfp_mask); + if (unlikely(!page_ext)) { + pr_alert("There is not page extension available.\n"); + return; + } + if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { pr_alert("page_owner info is not active (free page?)\n"); return; @@ -251,6 +273,8 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) } page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + continue; /* * Some pages could be missed by concurrent allocation or free, @@ -317,6 +341,8 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) continue; page_ext = lookup_page_ext(page); + if (unlikely(!page_ext)) + continue; /* Maybe overraping zone */ if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) |