From 541f40bda2743d5c6aef0ebeb09c6c89e5fcf37a Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 3 Feb 2004 18:48:48 -0800 Subject: [PATCH] [PATCH] proc_check_root() locking fix From: Maneesh Soni The patch fixes locking in proc_check_root(). It brings is_subdir() call under vfsmount_lock. Holding vfsmount_lock will ensure mnt_mountpoint dentry is intact and the dentry does not go away while it is being checked in is_subdir(). --- fs/proc/base.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 363af5b73d24f..7f2ab96dfd957 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -425,17 +425,15 @@ static int proc_check_root(struct inode *inode) mnt = vfsmnt; while (vfsmnt != our_vfsmnt) { - if (vfsmnt == vfsmnt->mnt_parent) { - spin_unlock(&vfsmount_lock); + if (vfsmnt == vfsmnt->mnt_parent) goto out; - } de = vfsmnt->mnt_mountpoint; vfsmnt = vfsmnt->mnt_parent; } - spin_unlock(&vfsmount_lock); if (!is_subdir(de, base)) goto out; + spin_unlock(&vfsmount_lock); exit: dput(base); @@ -444,6 +442,7 @@ exit: mntput(mnt); return res; out: + spin_unlock(&vfsmount_lock); res = -EACCES; goto exit; } -- 2.53.0