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From: Greg Thelen <gthelen@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Wu Fengguang <fengguang.wu@intel.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Greg Thelen <gthelen@google.com>
Subject: [PATCH] memcg: avoid overflow in memcg_hierarchical_free_pages()
Date: Mon,  8 Nov 2010 17:15:20 -0800	[thread overview]
Message-ID: <1289265320-7025-1-git-send-email-gthelen@google.com> (raw)

Use page counts rather than byte counts to avoid overflowing
unsigned long local variables.

Signed-off-by: Greg Thelen <gthelen@google.com>
---
 mm/memcontrol.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6c7115d..b287afd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1345,17 +1345,17 @@ memcg_hierarchical_free_pages(struct mem_cgroup *mem)
 {
 	unsigned long free, min_free;
 
-	min_free = global_page_state(NR_FREE_PAGES) << PAGE_SHIFT;
+	min_free = global_page_state(NR_FREE_PAGES);
 
 	while (mem) {
-		free = res_counter_read_u64(&mem->res, RES_LIMIT) -
-			res_counter_read_u64(&mem->res, RES_USAGE);
+		free = (res_counter_read_u64(&mem->res, RES_LIMIT) -
+			res_counter_read_u64(&mem->res, RES_USAGE)) >>
+			PAGE_SHIFT;
 		min_free = min(min_free, free);
 		mem = parent_mem_cgroup(mem);
 	}
 
-	/* Translate free memory in pages */
-	return min_free >> PAGE_SHIFT;
+	return min_free;
 }
 
 /*
-- 
1.7.3.1


WARNING: multiple messages have this Message-ID (diff)
From: Greg Thelen <gthelen@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Wu Fengguang <fengguang.wu@intel.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Greg Thelen <gthelen@google.com>
Subject: [PATCH] memcg: avoid overflow in memcg_hierarchical_free_pages()
Date: Mon,  8 Nov 2010 17:15:20 -0800	[thread overview]
Message-ID: <1289265320-7025-1-git-send-email-gthelen@google.com> (raw)

Use page counts rather than byte counts to avoid overflowing
unsigned long local variables.

Signed-off-by: Greg Thelen <gthelen@google.com>
---
 mm/memcontrol.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6c7115d..b287afd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1345,17 +1345,17 @@ memcg_hierarchical_free_pages(struct mem_cgroup *mem)
 {
 	unsigned long free, min_free;
 
-	min_free = global_page_state(NR_FREE_PAGES) << PAGE_SHIFT;
+	min_free = global_page_state(NR_FREE_PAGES);
 
 	while (mem) {
-		free = res_counter_read_u64(&mem->res, RES_LIMIT) -
-			res_counter_read_u64(&mem->res, RES_USAGE);
+		free = (res_counter_read_u64(&mem->res, RES_LIMIT) -
+			res_counter_read_u64(&mem->res, RES_USAGE)) >>
+			PAGE_SHIFT;
 		min_free = min(min_free, free);
 		mem = parent_mem_cgroup(mem);
 	}
 
-	/* Translate free memory in pages */
-	return min_free >> PAGE_SHIFT;
+	return min_free;
 }
 
 /*
-- 
1.7.3.1

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             reply	other threads:[~2010-11-09  1:16 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-09  1:15 Greg Thelen [this message]
2010-11-09  1:15 ` [PATCH] memcg: avoid overflow in memcg_hierarchical_free_pages() Greg Thelen
2010-11-09  1:28 ` Minchan Kim
2010-11-09  1:28   ` Minchan Kim
2010-11-09  1:47 ` Johannes Weiner
2010-11-09  1:47   ` Johannes Weiner
2010-11-09  3:44 ` Daisuke Nishimura
2010-11-09  3:44   ` Daisuke Nishimura
2010-11-09  3:52   ` Greg Thelen
2010-11-09  3:52     ` Greg Thelen
2010-11-16  3:45 ` KAMEZAWA Hiroyuki
2010-11-16  3:45   ` KAMEZAWA Hiroyuki

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