From db04dc679bcc780ad6907943afe24a30de974a1b Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 9 Mar 2013 00:14:45 -0800 Subject: [PATCH] proc: Use nd_jump_link in proc_ns_follow_link Update proc_ns_follow_link to use nd_jump_link instead of just manually updating nd.path.dentry. This fixes the BUG_ON(nd->inode != parent->d_inode) reported by Dave Jones and reproduced trivially with mkdir /proc/self/ns/uts/a. Sigh it looks like the VFS change to require use of nd_jump_link happend while proc_ns_follow_link was baking and since the common case of proc_ns_follow_link continued to work without problems the need for making this change was overlooked. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" --- fs/proc/namespaces.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c index b7a47196c8c3..66b51c0383da 100644 --- a/fs/proc/namespaces.c +++ b/fs/proc/namespaces.c @@ -118,7 +118,7 @@ static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd) struct super_block *sb = inode->i_sb; struct proc_inode *ei = PROC_I(inode); struct task_struct *task; - struct dentry *ns_dentry; + struct path ns_path; void *error = ERR_PTR(-EACCES); task = get_proc_task(inode); @@ -128,14 +128,14 @@ static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd) if (!ptrace_may_access(task, PTRACE_MODE_READ)) goto out_put_task; - ns_dentry = proc_ns_get_dentry(sb, task, ei->ns_ops); - if (IS_ERR(ns_dentry)) { - error = ERR_CAST(ns_dentry); + ns_path.dentry = proc_ns_get_dentry(sb, task, ei->ns_ops); + if (IS_ERR(ns_path.dentry)) { + error = ERR_CAST(ns_path.dentry); goto out_put_task; } - dput(nd->path.dentry); - nd->path.dentry = ns_dentry; + ns_path.mnt = mntget(nd->path.mnt); + nd_jump_link(nd, &ns_path); error = NULL; out_put_task: -- 2.20.1