From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964863AbcHaOic (ORCPT ); Wed, 31 Aug 2016 10:38:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:60560 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933835AbcHaOi3 (ORCPT ); Wed, 31 Aug 2016 10:38:29 -0400 X-IBM-Helo: d03dlp03.boulder.ibm.com X-IBM-MailFrom: arbab@linux.vnet.ibm.com From: Reza Arbab To: Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return value Date: Wed, 31 Aug 2016 09:38:22 -0500 X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <20160831122128.GA14689@kroah.com> References: <20160831122128.GA14689@kroah.com> X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16083114-0004-0000-0000-00001042763D X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00005686; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000184; SDB=6.00752120; UDB=6.00355568; IPR=6.00524931; BA=6.00004683; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00012534; XFM=3.00000011; UTC=2016-08-31 14:38:27 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16083114-0005-0000-0000-000078768C40 Message-Id: <1472654302-29788-1-git-send-email-arbab@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-08-31_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608310174 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Attempting to online memory which is already online will cause this: 1. store_mem_state() called with buf="online" 2. device_online() returns 1 because device is already online 3. store_mem_state() returns 1 4. calling code interprets this as 1-byte buffer read 5. store_mem_state() called again with buf="nline" 6. store_mem_state() returns -EINVAL Example: $ cat /sys/devices/system/memory/memory0/state online $ echo online > /sys/devices/system/memory/memory0/state -bash: echo: write error: Invalid argument Fix the return value of store_mem_state() so this doesn't happen. Signed-off-by: Reza Arbab --- drivers/base/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 1cea0ba..8e385ea 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -359,7 +359,7 @@ store_mem_state(struct device *dev, err: unlock_device_hotplug(); - if (ret) + if (ret < 0) return ret; return count; } -- 1.8.3.1