From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757563Ab3CNK7p (ORCPT ); Thu, 14 Mar 2013 06:59:45 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:51809 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756959Ab3CNKhO (ORCPT ); Thu, 14 Mar 2013 06:37:14 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Tejun Heo , Andrew Morton , Linus Torvalds , Luis Henriques Subject: [PATCH 25/88] block: fix synchronization and limit check in blk_alloc_devt() Date: Thu, 14 Mar 2013 10:35:18 +0000 Message-Id: <1363257381-15900-26-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1363257381-15900-1-git-send-email-luis.henriques@canonical.com> References: <1363257381-15900-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.8 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Tejun Heo commit ce23bba842aee98092225d9576dba47c82352521 upstream. idr allocation in blk_alloc_devt() wasn't synchronized against lookup and removal, and its limit check was off by one - 1 << MINORBITS is the number of minors allowed, not the maximum allowed minor. Add locking and rename MAX_EXT_DEVT to NR_EXT_DEVT and fix limit checking. Signed-off-by: Tejun Heo Acked-by: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques --- block/genhd.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 9433636..60108d9 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -25,7 +25,7 @@ static DEFINE_MUTEX(block_class_lock); struct kobject *block_depr; /* for extended dynamic devt allocation, currently only one major is used */ -#define MAX_EXT_DEVT (1 << MINORBITS) +#define NR_EXT_DEVT (1 << MINORBITS) /* For extended devt allocation. ext_devt_mutex prevents look up * results from going away underneath its user. @@ -422,19 +422,16 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt) return -ENOMEM; mutex_lock(&ext_devt_mutex); rc = idr_get_new(&ext_devt_idr, part, &idx); + if (!rc && idx >= NR_EXT_DEVT) { + idr_remove(&ext_devt_idr, idx); + rc = -EBUSY; + } mutex_unlock(&ext_devt_mutex); } while (rc == -EAGAIN); if (rc) return rc; - if (idx > MAX_EXT_DEVT) { - mutex_lock(&ext_devt_mutex); - idr_remove(&ext_devt_idr, idx); - mutex_unlock(&ext_devt_mutex); - return -EBUSY; - } - *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx)); return 0; } -- 1.8.1.2