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authorYang Shi <yang.shi@linaro.org>2016-06-03 14:55:38 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-24 08:32:25 +0100
commite34e744f70a68f8f16f945a286802898c56a8b5a (patch)
tree8f8d3bd244b194e9a3df7e988297436427783286 /mm
parent7b7a1c39e8394d4232714093882b733b3e435c67 (diff)
mm: check the return value of lookup_page_ext for all call sites
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.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> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/debug-pagealloc.c6
-rw-r--r--mm/page_alloc.c6
-rw-r--r--mm/page_owner.c16
-rw-r--r--mm/vmstat.c2
4 files changed, 30 insertions, 0 deletions
diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
index 5bf5906ce13b..fe1c61f7cf26 100644
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -34,6 +34,8 @@ static inline void set_page_poison(struct page *page)
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(struct page *page)
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 page *page)
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);
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 35ce37b187f9..3c70f03d91ec 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -569,6 +569,9 @@ 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);
@@ -586,6 +589,9 @@ 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);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 983c3a10fa07..dd6b9cebf981 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -53,6 +53,8 @@ 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);
}
}
@@ -60,6 +62,7 @@ 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),
@@ -67,6 +70,9 @@ 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;
@@ -79,6 +85,12 @@ void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
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 __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,
@@ -257,6 +271,8 @@ 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))
diff --git a/mm/vmstat.c b/mm/vmstat.c
index c54fd2924f25..c344e3609c53 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1091,6 +1091,8 @@ 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;