Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752959AbaFFD5z (ORCPT ); Thu, 5 Jun 2014 23:57:55 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:1529 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752892AbaFFD5x (ORCPT ); Thu, 5 Jun 2014 23:57:53 -0400 X-IronPort-AV: E=Sophos;i="4.98,986,1392134400"; d="scan'208";a="31545953" From: Tang Chen To: , , , , , , CC: , , , , Subject: [PATCH v2 1/2] mem-hotplug: Avoid illegal state prefixed with legal state when changing state of memory_block. Date: Fri, 6 Jun 2014 11:58:53 +0800 Message-ID: <1402027134-14423-2-git-send-email-tangchen@cn.fujitsu.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1402027134-14423-1-git-send-email-tangchen@cn.fujitsu.com> References: <1402027134-14423-1-git-send-email-tangchen@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.99] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We use the following command to online a memory_block: echo online|online_kernel|online_movable > /sys/devices/system/memory/memoryXXX/state But, if we do the following: echo online_fhsjkghfkd > /sys/devices/system/memory/memoryXXX/state the block will also be onlined. This is because the following code in store_mem_state() does not compare the whole string, but only the prefix of the string. store_mem_state() { ...... 328 if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) Here, only compare the first 13 letters of the string. If we give "online_kernelXXXXXX", it will be recognized as online_kernel, which is incorrect. 329 online_type = ONLINE_KERNEL; 330 else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) We have the same problem here, 331 online_type = ONLINE_MOVABLE; 332 else if (!strncmp(buf, "online", min_t(int, count, 6))) here, (Here is more problematic. If we give online_movalbe, which is a typo of online_movable, it will be recognized as online without noticing the author.) 333 online_type = ONLINE_KEEP; 334 else if (!strncmp(buf, "offline", min_t(int, count, 7))) and here. 335 online_type = -1; 336 else { 337 ret = -EINVAL; 338 goto err; 339 } ...... } This patch fix this problem by using sysfs_streq() to compare the whole string. Reported-by: Hu Tao Signed-off-by: Tang Chen --- change log v1 -> v2: Following Andrew's suggestion, use sysfs_streq() to compare the whole string so that we can simplify the code. --- --- drivers/base/memory.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index bece691..fa664b9 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -325,13 +325,13 @@ store_mem_state(struct device *dev, if (ret) return ret; - if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) + if (sysfs_streq(buf, "online_kernel")) online_type = ONLINE_KERNEL; - else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) + else if (sysfs_streq(buf, "online_movable")) online_type = ONLINE_MOVABLE; - else if (!strncmp(buf, "online", min_t(int, count, 6))) + else if (sysfs_streq(buf, "online")) online_type = ONLINE_KEEP; - else if (!strncmp(buf, "offline", min_t(int, count, 7))) + else if (sysfs_streq(buf, "offline")) online_type = -1; else { ret = -EINVAL; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/