Commit f86e4271 authored by Yang Shi's avatar Yang Shi Committed by Linus Torvalds

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.orgSigned-off-by: 's avatarYang Shi <yang.shi@linaro.org>
Signed-off-by: 's avatarArnd Bergmann <arnd@arndb.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d8bae33d
......@@ -46,33 +46,62 @@ extern struct page_ext_operations page_idle_ops;
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 */
......
......@@ -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);
......
......@@ -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))
......
......@@ -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);
......
......@@ -1061,6 +1061,8 @@ static void pagetypeinfo_showmixedcount_print(struct seq_file *m,
continue;
page_ext = lookup_page_ext(page);
if (unlikely(!page_ext))
continue;
if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
continue;
......
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