linux-kernel - Re: [PATCH] configfs: Fix config_item refcnt error in __configfs_open

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Date:   Thu, 11 Mar 2021 12:29:59 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Christoph Hellwig <hch@....de>
Cc:     Joel Becker <jlbec@...lplan.org>, linux-kernel@...r.kernel.org,
        Al Viro <viro@...iv.linux.org.uk>,
        Daniel Rosenberg <drosen@...gle.com>, stable@...r.kernel.org
Subject: Re: [PATCH] configfs: Fix config_item refcnt error in
 __configfs_open_file()

On Thu, Mar 11, 2021 at 12:16:25PM +0100, Christoph Hellwig wrote:
> I've actually just queued up a similar patch from Daiyue Zhang.
> 
> > -		goto out_put_item;
> > +		goto out_put_module;
> >  
> >  	if (type & CONFIGFS_ITEM_BIN_ATTR) {
> >  		buffer->bin_attr = to_bin_attr(dentry);
> > @@ -391,7 +391,7 @@ static int __configfs_open_file(struct inode *inode, struct file *file, int type
> >  	/* Grab the module reference for this attribute if we have one */
> >  	error = -ENODEV;
> >  	if (!try_module_get(buffer->owner))
> > -		goto out_put_item;
> > +		goto out_put_module;
> >  
> >  	error = -EACCES;
> >  	if (!buffer->item->ci_type)
> > @@ -435,8 +435,6 @@ static int __configfs_open_file(struct inode *inode, struct file *file, int type
> >  
> >  out_put_module:
> >  	module_put(buffer->owner);
> > -out_put_item:
> > -	config_item_put(buffer->item);
> >  out_free_buffer:
> 
> But the goto labe changes here look incorrect anyway, as they now introduce
> a double put on the module..

Oops, should be one label lower.  Daniel must not have checked this on
a system with modules :)

Let me go fix this up...

thanks,

greg k-h