From: Joel Becker <jlbec@evilplan.org>
To: Jiri Slaby <jslaby@suse.cz>
Cc: npiggin@kernel.dk, Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Jiri Slaby <jirislaby@gmail.com>
Subject: Re: OOPS in configfs when doing d_delete
Date: Mon, 21 Feb 2011 02:44:01 -0800 [thread overview]
Message-ID: <20110221104359.GA18538@noexit> (raw)
In-Reply-To: <4D623C62.8030509@suse.cz>
On Mon, Feb 21, 2011 at 11:20:18AM +0100, Jiri Slaby wrote:
> when configfs_attach_group fails in configfs_register_subsystem:
> dentry = d_alloc(configfs_sb->s_root, &name);
> if (dentry) {
> d_add(dentry, NULL);
>
> err = configfs_attach_group(sd->s_element, &group->cg_item,
> dentry);
> if (err) {
> d_delete(dentry);
> dput(dentry);
>
>
> d_delete kills the kernel. I don't know what the actual bug is here, but
> d_delete looks broken anyway:
> spin_lock(&dentry->d_lock);
> inode = dentry->d_inode;
> isdir = S_ISDIR(inode->i_mode); <======== dereference
> if (dentry->d_count == 1) {
> if (inode && !spin_trylock(&inode->i_lock)) {
> ^^^^^ <============= test
>
> It seems like a superfluous test, not a potential null dereference to
> me, right?
I think you're right about the superfluous test, but I need more
investigation to see what's going on. Thanks for the report.
What was causing attach_group() to fail? Do you know?
Joel
--
Life's Little Instruction Book #444
"Never underestimate the power of a kind word or deed."
http://www.jlbec.org/
jlbec@evilplan.org
next prev parent reply other threads:[~2011-02-21 10:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-21 10:20 OOPS in configfs when doing d_delete Jiri Slaby
2011-02-21 10:44 ` Joel Becker [this message]
2011-02-21 10:47 ` Jiri Slaby
2011-02-22 9:14 ` Joel Becker
2011-03-01 22:42 ` Jiri Slaby
2011-05-12 9:34 ` Jiri Slaby
2011-05-18 19:58 ` Joel Becker
2011-05-27 21:12 ` Jiri Slaby
2011-05-27 21:13 ` Joel Becker
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