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From: Firo Yang <firogm@gmail.com>
To: akpm@linux-foundation.org
Cc: vbabka@suse.cz, mgorman@techsingularity.net, hannes@cmpxchg.org,
	mhocko@suse.com, bigeasy@linutronix.de, iamjoonsoo.kim@lge.com,
	rientjes@google.com, hughd@google.com, cl@linux.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Firo Yang <firogm@gmail.com>
Subject: [PATCH] mm, vmstat: Fix NULL pointer dereference during pagetypeinfo print
Date: Fri, 19 May 2017 22:39:36 +0800	[thread overview]
Message-ID: <20170519143936.21209-1-firogm@gmail.com> (raw)

During showing the pagetypeinfo, we forgot to save the found page
and dereference a invalid page address from the stack.

To fix it, save and reference the page address returned by
pfn_to_online_page().

Signed-off-by: Firo Yang <firogm@gmail.com>
---
 mm/vmstat.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index c432e58..6dae6b2 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1223,7 +1223,8 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 		struct page *page;
 
-		if (!pfn_to_online_page(pfn))
+		page = pfn_to_online_page(pfn);
+		if (!page)
 			continue;
 
 		/* Watch for unexpected holes punched in the memmap */
-- 
2.9.4

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WARNING: multiple messages have this Message-ID (diff)
From: Firo Yang <firogm@gmail.com>
To: akpm@linux-foundation.org
Cc: vbabka@suse.cz, mgorman@techsingularity.net, hannes@cmpxchg.org,
	mhocko@suse.com, bigeasy@linutronix.de, iamjoonsoo.kim@lge.com,
	rientjes@google.com, hughd@google.com, cl@linux.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Firo Yang <firogm@gmail.com>
Subject: [PATCH] mm, vmstat: Fix NULL pointer dereference during pagetypeinfo print
Date: Fri, 19 May 2017 22:39:36 +0800	[thread overview]
Message-ID: <20170519143936.21209-1-firogm@gmail.com> (raw)

During showing the pagetypeinfo, we forgot to save the found page
and dereference a invalid page address from the stack.

To fix it, save and reference the page address returned by
pfn_to_online_page().

Signed-off-by: Firo Yang <firogm@gmail.com>
---
 mm/vmstat.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index c432e58..6dae6b2 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1223,7 +1223,8 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 		struct page *page;
 
-		if (!pfn_to_online_page(pfn))
+		page = pfn_to_online_page(pfn);
+		if (!page)
 			continue;
 
 		/* Watch for unexpected holes punched in the memmap */
-- 
2.9.4

             reply	other threads:[~2017-05-19 14:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-19 14:39 Firo Yang [this message]
2017-05-19 14:39 ` [PATCH] mm, vmstat: Fix NULL pointer dereference during pagetypeinfo print Firo Yang
2017-05-19 14:48 ` Michal Hocko
2017-05-19 14:48   ` Michal Hocko

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