linux-kernel - [PATCH 3/3] cgroup: fix strstrip() abuse

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Message-Id: <20091002173955.5F72.A69D9226@jp.fujitsu.com>
Date:	Fri,  2 Oct 2009 17:41:08 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	kosaki.motohiro@...fujitsu.com, linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Li Zefan <lizf@...fujitsu.com>, Paul Menage <menage@...gle.com>
Subject: [PATCH 3/3] cgroup: fix strstrip() abuse

cgroup_write_X64() and cgroup_write_string() ignore the return
value of strstrip().
it makes small inconsistent behavior.

example: 
=========================
 # cd /mnt/cgroup/hoge
 # cat memory.swappiness
 60
 # echo "59 " > memory.swappiness
 # cat memory.swappiness
 59
 # echo " 58" > memory.swappiness
 bash: echo: write error: Invalid argument


This patch fixes it.

Cc: Li Zefan <lizf@...fujitsu.com>
Cc: Paul Menage <menage@...gle.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
---
 kernel/cgroup.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

Index: b/kernel/cgroup.c
===================================================================
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1710,14 +1710,13 @@ static ssize_t cgroup_write_X64(struct c
 		return -EFAULT;
 
 	buffer[nbytes] = 0;     /* nul-terminate */
-	strstrip(buffer);
 	if (cft->write_u64) {
-		u64 val = simple_strtoull(buffer, &end, 0);
+		u64 val = simple_strtoull(strstrip(buffer), &end, 0);
 		if (*end)
 			return -EINVAL;
 		retval = cft->write_u64(cgrp, cft, val);
 	} else {
-		s64 val = simple_strtoll(buffer, &end, 0);
+		s64 val = simple_strtoll(strstrip(buffer), &end, 0);
 		if (*end)
 			return -EINVAL;
 		retval = cft->write_s64(cgrp, cft, val);
@@ -1753,8 +1752,7 @@ static ssize_t cgroup_write_string(struc
 	}
 
 	buffer[nbytes] = 0;     /* nul-terminate */
-	strstrip(buffer);
-	retval = cft->write_string(cgrp, cft, buffer);
+	retval = cft->write_string(cgrp, cft, strstrip(buffer));
 	if (!retval)
 		retval = nbytes;
 out:


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