From: Al Viro <viro@ZenIV.linux.org.uk>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC][PATCH] debugfs: Fix corrupted loop in debugfs_remove_recursive
Date: Thu, 12 Jun 2014 11:43:14 +0100 [thread overview]
Message-ID: <20140612104314.GB18016@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20140609140607.3e3aae39@gandalf.local.home>
On Mon, Jun 09, 2014 at 02:06:07PM -0400, Steven Rostedt wrote:
> When these are called, the d_entry and inode locks need to be released
> to call the instance creation and deletion code. That code has its own
> accounting and locking to serialize everything to prevent multiple
> users from causing harm. As the parent "instance" directory can not
> be modified this simplifies things.
Yecchhh... Looking at debugfs:
static inline int debugfs_positive(struct dentry *dentry)
{
return dentry->d_inode && !d_unhashed(dentry);
}
...
if (debugfs_positive(dentry)) {
if (dentry->d_inode) {
What the hell?
parent = dentry->d_parent;
if (!parent || !parent->d_inode)
return;
Huh? First of all, ->d_parent is *never* NULL. Moreover, it can't be a
negative dentry.
What's more, if debugfs_rename() is ever used for cross-directory renames,
this tree-walker is buggered - it'll happily walk up "back" into a directory
it has never visited...
next prev parent reply other threads:[~2014-06-12 10:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-09 18:06 [RFC][PATCH] debugfs: Fix corrupted loop in debugfs_remove_recursive Steven Rostedt
2014-06-10 13:33 ` Steven Rostedt
2014-06-10 20:23 ` Greg Kroah-Hartman
2014-06-10 20:22 ` Steven Rostedt
2014-06-10 20:33 ` Greg Kroah-Hartman
2014-06-30 15:53 ` Steven Rostedt
2014-06-30 16:26 ` Greg Kroah-Hartman
2014-06-12 10:43 ` Al Viro [this message]
2014-06-12 16:08 ` Greg Kroah-Hartman
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