From: Yang Shi <yang.shi@linaro.org>
To: akpm@linux-foundation.org, iamjoonsoo.kim@lge.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linaro-kernel@lists.linaro.org, yang.shi@linaro.org
Subject: [PATCH] mm: check the return value of lookup_page_ext for all call sites
Date: Mon, 23 May 2016 10:16:08 -0700 [thread overview]
Message-ID: <1464023768-31025-1-git-send-email-yang.shi@linaro.org> (raw)
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
Signed-off-by: Yang Shi <yang.shi@linaro.org>
---
include/linux/page_idle.h | 43 ++++++++++++++++++++++++++++++++++++-------
mm/page_alloc.c | 6 ++++++
mm/page_owner.c | 27 +++++++++++++++++++++++++++
mm/page_poison.c | 8 +++++++-
mm/vmstat.c | 2 ++
5 files changed, 78 insertions(+), 8 deletions(-)
diff --git a/include/linux/page_idle.h b/include/linux/page_idle.h
index bf268fa..8f5d4ad 100644
--- a/include/linux/page_idle.h
+++ b/include/linux/page_idle.h
@@ -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;
+ 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;
+ 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;
+ 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;
+ 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;
+ 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;
+ page_ext = lookup_page_ext(page);
+ if (unlikely(!page_ext)
+ return;
+
+ clear_bit(PAGE_EXT_IDLE, &page_ext->flags);
}
#endif /* CONFIG_64BIT */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f8f3bfc..d27e8b9 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);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 792b56d..902e398 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 +64,10 @@ 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);
+
+ if (unlikely(!page_ext))
+ return;
+
struct stack_trace trace = {
.nr_entries = 0,
.max_entries = ARRAY_SIZE(page_ext->trace_entries),
@@ -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;
}
@@ -97,6 +111,10 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage)
{
struct page_ext *old_ext = lookup_page_ext(oldpage);
struct page_ext *new_ext = lookup_page_ext(newpage);
+
+ if (unlikely(!old_ext || !new_ext))
+ return;
+
int i;
new_ext->order = old_ext->order;
@@ -186,6 +204,11 @@ err:
void __dump_page_owner(struct page *page)
{
struct page_ext *page_ext = lookup_page_ext(page);
+ if (unlikely(!page_ext)) {
+ pr_alert("There is not page extension available.\n");
+ return;
+ }
+
struct stack_trace trace = {
.nr_entries = page_ext->nr_entries,
.entries = &page_ext->trace_entries[0],
@@ -251,6 +274,8 @@ 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 +342,8 @@ 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/page_poison.c b/mm/page_poison.c
index 1eae5fa..2e647c6 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);
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 77e42ef..cb2a67b 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -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;
--
2.0.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next reply other threads:[~2016-05-23 17:43 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-23 17:16 Yang Shi [this message]
2016-05-24 2:58 ` [PATCH] mm: check the return value of lookup_page_ext for all call sites Minchan Kim
2016-05-26 0:37 ` Minchan Kim
2016-05-26 23:15 ` Shi, Yang
2016-05-27 5:14 ` Minchan Kim
2016-05-27 6:08 ` Joonsoo Kim
2016-05-27 8:11 ` Minchan Kim
2016-05-27 18:16 ` Shi, Yang
2016-05-30 6:11 ` Minchan Kim
2016-06-01 20:40 ` Shi, Yang
2016-06-02 5:00 ` Minchan Kim
2016-06-02 23:15 ` Shi, Yang
2016-05-30 5:39 ` Joonsoo Kim
2016-05-30 6:08 ` Minchan Kim
2016-06-01 20:52 ` Shi, Yang
2016-05-27 20:02 ` Andrew Morton
2016-05-27 20:17 ` Shi, Yang
2016-05-27 20:30 ` Andrew Morton
2016-05-24 10:08 ` [PATCH] mm: fix build problems from lookup_page_ext Arnd Bergmann
2016-05-24 16:33 ` Shi, Yang
2016-05-25 7:12 ` [PATCH] mm: check the return value of lookup_page_ext for all call sites shakil
2016-05-30 6:17 ` Minchan Kim
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1464023768-31025-1-git-send-email-yang.shi@linaro.org \
--to=yang.shi@linaro.org \
--cc=akpm@linux-foundation.org \
--cc=iamjoonsoo.kim@lge.com \
--cc=linaro-kernel@lists.linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).