From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, nuxi@vault24.org Date: Tue, 17 Feb 2015 01:46:53 +0000 Message-ID: Subject: [PATCH 3.2 148/152] vfs: Fix vfsmount_lock imbalance in path_init() In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings When backporting commit 4023bfc9f351 ("be careful with nd->inode in path_init() and follow_dotdot_rcu()"), I failed to account for the vfsmount_lock that is used in 3.2 but not upstream. path_init() takes the lock if performing RCU lookup, but must drop it if (and only if) it subsequently fails. Reported-by: nuxi@vault24.org References: https://bugzilla.kernel.org/show_bug.cgi?id=92531 Signed-off-by: Ben Hutchings Tested-by: nuxi@vault24.org --- --- a/fs/namei.c +++ b/fs/namei.c @@ -1567,6 +1567,7 @@ static int path_init(int dfd, const char if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; rcu_read_unlock(); + br_read_unlock(vfsmount_lock); return -ECHILD; fput_fail: