From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755944AbcEESlu (ORCPT ); Thu, 5 May 2016 14:41:50 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:45504 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754684AbcEESlt (ORCPT ); Thu, 5 May 2016 14:41:49 -0400 X-IBM-Helo: d03dlp02.boulder.ibm.com X-IBM-MailFrom: arbab@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: Reza Arbab To: Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: [PATCH] memory-hotplug: fix store_mem_state() return value Date: Thu, 5 May 2016 13:41:44 -0500 Message-Id: <1462473704-10671-1-git-send-email-arbab@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.3.1 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16050518-0017-0000-0000-00002A6D63C8 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused 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 | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 961e2cf..031950f 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -359,9 +359,7 @@ store_mem_state(struct device *dev, err: unlock_device_hotplug(); - if (ret) - return ret; - return count; + return ret < 0 ? ret : count; } /* -- 1.8.3.1